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C++ || Simple Multi Digit, Decimal & Negative Number Infix To Postfix Conversion & Evaluation

February 05, 2021 admin No comments

The following is sample code which demonstrates the implementation of a multi digit, decimal, and negative number infix to postfix converter and evaluator using C++.

The program demonstrated on this page has the ability to convert and evaluate a single digit, multi digit, decimal number, and/or negative number infix equation. So for example, if the the infix equation of (19.87 * -2) was entered into the program, the converted postfix expression of 19.87 -2 * would display to the screen, as well as the final evaluated answer of -39.74.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

How To Convert Infix To Postfix How To Evaluate A Postfix Expression

1. Overview

The program demonstrated on this page is different from a previous implementation of the same type in that this version does not use a Finite State Machine during the conversion process, which simplifies the implemetation!

This program has the following flow of control:

• Get an infix expression from the user • Convert the infix expression to postfix & isolate all of the math operators, multi digit, decimal, negative and single digit numbers that are found in the postfix expression • Evaluate the postfix expression by breaking the infix string into tokens found from the above step • Display the evaluated answer to the screen

The above steps are implemented below.

2. Infix To Posfix Conversion & Evaluation





		
		
			Multi Digit Infix To Postfix Conversion & Evaluation
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 31, 2014
//    Updated: Feb 5, 2021
//    Taken From: http://programmingnotes.org/
//    File: InToPostEval.cpp
//    Description: The following demonstrates the implementation of an infix to
//      postfix converter and evaluator. This program has the ability to
//      convert and evaluate multi digit, decimal, negative and positive values
// ============================================================================
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <stack>
#include <algorithm>
#include <exception>
#include <stdexcept>

// function prototypes
void displayDirections();
std::string convertInfixToPostfix(std::string infix);
bool isMathOperator(char token);
int orderOfOperations(char token);
double evaluatePostfix(const std::string& postfix);
double calculate(char mathOperator, double value1, double value2);
bool isNumeric(char value);
bool isNumeric(std::string value);
std::vector<std::string> split(const std::string& source, const std::string& delimiters = " ");
std::string replaceAll(const std::string& source
    , const std::string& oldValue, const std::string& newValue);

int main() {
    // declare variables
    std::string infix = "";

    // display directions to user
    displayDirections();

    try {
        // get data from user
        std::cout << "\nPlease enter an Infix expression: ";
        std::getline(std::cin, infix);

        // convert infix to postfix
        std::string postfix = convertInfixToPostfix(infix);

        std::cout << "\nThe Infix expression = " << infix;
        std::cout << "\nThe Postfix expression = " << postfix << std::endl;

        // evaluate the postfix string
        double answer = evaluatePostfix(postfix);

        std::cout << "\nFinal answer = " << answer << std::endl;
    } catch (std::exception& e) {
        std::cout << "\nAn error occurred: " + std::string(e.what()) << std::endl;
    }

    std::cin.get();
    return 0;
}// end of main

void displayDirections() {
// this function displays instructions to the screen
    std::cout << "\n==== Infix To Postfix Conversion & Evaluation ====\n"
        << "\nMath Operators:\n"
        << "+ || Addition\n"
        << "- || Subtraction\n"
        << "* || Multiplication\n"
        << "/ || Division\n"
        << "% || Modulus\n"
        << "^ || Power\n"
        << "$ || Square Root\n"
        << "s || Sine\n"
        << "c || Cosine\n"
        << "t || Tangent\n"
        << "- || Negative Number\n"
        << "Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23))\n";
    // ((sin(-4^5)*1.4)/(sqrt(23+2)--2.8))*(cos(1%2)/(7.28*.1987)^(tan(23)))
}// end of displayDirections

std::string convertInfixToPostfix(std::string infix) {
// this function converts an infix expression to postfix
        // declare function variables
    std::string postfix;
    std::stack<char> charStack;

    // remove all whitespace from the string
    infix.erase(std::remove_if(infix.begin(), infix.end(), [](char c) {
        return std::isspace(static_cast<unsigned char>(c));
    }), infix.end());

    // negate equations marked with '--'
    infix = replaceAll(infix, "(--", "(");

    // automatically convert negative numbers to have the ~ symbol.
    // this is done so we can distinguish negative numbers and the subtraction symbol
    for (unsigned x = 0; x < infix.length(); ++x) {
        if (infix[x] != '-') {
            continue;
        }
        if (x == 0 || infix[x - 1] == '(' || isMathOperator(infix[x - 1])) {
            infix[x] = '~';
        }
    }

    // loop thru array until there is no more data
    for (unsigned x = 0; x < infix.length(); ++x) {
        // place numbers (standard, decimal, & negative)
        // numbers onto the 'postfix' string
        if (isNumeric(infix[x])) {
            if (postfix.length() > 0 && !isNumeric(postfix.back())) {
                if (!std::isspace(postfix.back())) {
                    postfix += " ";
                }
            }
            postfix += infix[x];

        } else if (std::isspace(infix[x])) {
            continue;

        } else if (isMathOperator(infix[x])) {
            if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                postfix += " ";
            }
            // use the 'orderOfOperations' function to check equality
            // of the math operator at the top of the stack compared to
            // the current math operator in the infix string
            while ((!charStack.empty()) &&
                (orderOfOperations(charStack.top()) >= orderOfOperations(infix[x]))) {
                // place the math operator from the top of the
                // stack onto the postfix string and continue the
                // process until complete
                if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                    postfix += " ";
                }
                postfix += charStack.top();
                charStack.pop();
            }
            // push the remaining math operator onto the stack
            charStack.push(infix[x]);
        }
        // push outer parentheses onto stack
        else if (infix[x] == '(') {
            charStack.push(infix[x]);

        } else if (infix[x] == ')') {
            // pop the current math operator from the stack
            while ((!charStack.empty()) && (charStack.top() != '(')) {
                if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                    postfix += " ";
                }
                // place the math operator onto the postfix string
                postfix += charStack.top();
                // pop the next operator from the stack and
                // continue the process until complete
                charStack.pop();
            }

            // pop '(' symbol off the stack
            if (!charStack.empty()) {
                charStack.pop();
            } else {
                // no matching '('
                throw std::invalid_argument{ "PARENTHESES MISMATCH" };
            }
        } else {
            throw std::invalid_argument{ "INVALID INPUT" };
        }
    }

    // place any remaining math operators from the stack onto
    // the postfix array
    while (!charStack.empty()) {
        if (charStack.top() == '(' || charStack.top() == ')') {
            throw std::invalid_argument{ "PARENTHESES MISMATCH" };
        }
        if (postfix.length() > 0 && !std::isspace(postfix.back())) {
            postfix += " ";
        }
        postfix += charStack.top();
        charStack.pop();
    }

    // replace all '~' symbols with a minus sign
    postfix = replaceAll(postfix, "~", "-");

    return postfix;
}// end of convertInfixToPostfix

bool isMathOperator(char token) {
// this function checks if operand is a math operator
    switch (std::tolower(token)) {
        case '+': case '-': case '*': case '/':
        case '%': case '^': case '$': case 'c':
        case 's': case 't':
            return true;
            break;
        default:
            return false;
            break;
    }
}// end of isMathOperator

int orderOfOperations(char token) {
// this function returns the priority of each math operator
    int priority = 0;
    switch (std::tolower(token)) {
        case 'c': case 's': case 't':
            priority = 5;
            break;
        case '^': case '$':
            priority = 4;
            break;
        case '*': case '/': case '%':
            priority = 3;
            break;
        case '-':
            priority = 2;
            break;
        case '+':
            priority = 1;
            break;
    }
    return priority;
}// end of orderOfOperations

double evaluatePostfix(const std::string& postfix) {
// this function evaluates a postfix expression
    // declare function variables
    double answer = 0;
    std::stack<double> doubleStack;

    // split string into tokens to isolate multi digit, negative and decimal
    // numbers, aswell as single digit numbers and math operators
    auto tokens = split(postfix);

    // display the found tokens to the screen
    //for (unsigned x = 0; x < tokens.size(); ++x) {
    //    std::cout<< tokens.at(x) << std::endl;
    //}

    std::cout << "\nCalculations:\n";

    // loop thru array until there is no more data
    for (unsigned x = 0; x < tokens.size(); ++x) {
        auto token = tokens[x];

        // push numbers & negative numbers onto the stack
        if (isNumeric(token)) {
            doubleStack.push(std::atof(token.c_str()));
        }
        // if expression is a math operator, pop numbers from stack
        // & send the popped numbers to the 'calculate' function
        else if (isMathOperator(token[0]) && (!doubleStack.empty())) {
            double value1 = 0;
            double value2 = 0;
            char mathOperator = static_cast<unsigned char>(std::tolower(token[0]));

            // if expression is square root, sin, cos,
            // or tan operation only pop stack once
            if (mathOperator == '$' || mathOperator == 's' || mathOperator == 'c' || mathOperator == 't') {
                value2 = 0;
                value1 = doubleStack.top();
                doubleStack.pop();
                answer = calculate(mathOperator, value1, value2);
                doubleStack.push(answer);

            } else if (doubleStack.size() > 1) {
                value2 = doubleStack.top();
                doubleStack.pop();
                value1 = doubleStack.top();
                doubleStack.pop();
                answer = calculate(mathOperator, value1, value2);
                doubleStack.push(answer);
            }
        } else {
            // this should never execute, & if it does, something went really wrong
            throw std::invalid_argument{ "INVALID POSTFIX STRING" };
        }
    }
    // pop the final answer from the stack, and return to main
    if (!doubleStack.empty()) {
        answer = doubleStack.top();
    }
    return answer;
}// end of evaluatePostfix

double calculate(char mathOperator, double value1, double value2) {
// this function carries out the actual math process
    double ans = 0;
    switch (std::tolower(mathOperator)) {
        case '+':
            std::cout << value1 << mathOperator << value2;
            ans = value1 + value2;
            break;
        case '-':
            std::cout << value1 << mathOperator << value2;
            ans = value1 - value2;
            break;
        case '*':
            std::cout << value1 << mathOperator << value2;
            ans = value1 * value2;
            break;
        case '/':
            std::cout << value1 << mathOperator << value2;
            ans = value1 / value2;
            break;
        case '%':
            std::cout << value1 << mathOperator << value2;
            ans = ((int)value1 % (int)value2) + std::modf(value1, &value2);
            break;
        case '^':
            std::cout << value1 << mathOperator << value2;
            ans = std::pow(value1, value2);
            break;
        case '$':
            std::cout << char(251) << value1;
            ans = std::sqrt(value1);
            break;
        case 'c':
            std::cout << "cos(" << value1 << ")";
            ans = std::cos(value1);
            break;
        case 's':
            std::cout << "sin(" << value1 << ")";
            ans = std::sin(value1);
            break;
        case 't':
            std::cout << "tan(" << value1 << ")";
            ans = std::tan(value1);
            break;
        default:
            ans = 0;
            break;
    }
    std::cout << " = " << ans << std::endl;
    return ans;
}// end of calculate

std::vector<std::string> split(const std::string& source, const std::string& delimiters) {
    std::size_t prev = 0;
    std::size_t currentPos = 0;
    std::vector<std::string> results;

    while ((currentPos = source.find_first_of(delimiters, prev)) != std::string::npos) {
        if (currentPos > prev) {
            results.push_back(source.substr(prev, currentPos - prev));
        }
        prev = currentPos + 1;
    }
    if (prev < source.length()) {
        results.push_back(source.substr(prev, std::string::npos));
    }
    return results;
}// end of split

std::string replaceAll(const std::string& source
    , const std::string& oldValue, const std::string& newValue) {
    if (oldValue.empty()) {
        return source;
    }
    std::string newString;
    newString.reserve(source.length());
    std::size_t lastPos = 0;
    std::size_t findPos;
    while (std::string::npos != (findPos = source.find(oldValue, lastPos))) {
        newString.append(source, lastPos, findPos - lastPos);
        newString += newValue;
        lastPos = findPos + oldValue.length();
    }
    newString += source.substr(lastPos);
    return newString;
}// end of replaceAll

bool isNumeric(char value) {
    return std::isdigit(value) || value == '.' || value == '~';
}// end of isNumeric

bool isNumeric(std::string value) {
    for (unsigned index = 0; index < value.length(); ++index) {
        if (index == 0 && value[index] == '-' && value.length() > 1) {
            continue;
        }
        if (!isNumeric(value[index])) {
            return false;
        }
    }
    return true;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 31, 2014
//    Updated: Feb 5, 2021
//    Taken From: http://programmingnotes.org/
//    File: InToPostEval.cpp
//    Description: The following demonstrates the implementation of an infix to
//      postfix converter and evaluator. This program has the ability to
//      convert and evaluate multi digit, decimal, negative and positive values
// ============================================================================
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <stack>
#include <algorithm>
#include <exception>
#include <stdexcept>
 
// function prototypes
void displayDirections();
std::string convertInfixToPostfix(std::string infix);
bool isMathOperator(char token);
int orderOfOperations(char token);
double evaluatePostfix(const std::string& postfix);
double calculate(char mathOperator, double value1, double value2);
bool isNumeric(char value);
bool isNumeric(std::string value);
std::vector<std::string> split(const std::string& source, const std::string& delimiters = " ");
std::string replaceAll(const std::string& source
    , const std::string& oldValue, const std::string& newValue);
 
int main() {
    // declare variables
    std::string infix = "";
 
    // display directions to user
    displayDirections();
 
    try {
        // get data from user
        std::cout << "\nPlease enter an Infix expression: ";
        std::getline(std::cin, infix);
 
        // convert infix to postfix
        std::string postfix = convertInfixToPostfix(infix);
 
        std::cout << "\nThe Infix expression = " << infix;
        std::cout << "\nThe Postfix expression = " << postfix << std::endl;
 
        // evaluate the postfix string
        double answer = evaluatePostfix(postfix);
 
        std::cout << "\nFinal answer = " << answer << std::endl;
    } catch (std::exception& e) {
        std::cout << "\nAn error occurred: " + std::string(e.what()) << std::endl;
    }
 
    std::cin.get();
    return 0;
}// end of main
 
void displayDirections() {
// this function displays instructions to the screen
    std::cout << "\n==== Infix To Postfix Conversion & Evaluation ====\n"
        << "\nMath Operators:\n"
        << "+ || Addition\n"
        << "- || Subtraction\n"
        << "* || Multiplication\n"
        << "/ || Division\n"
        << "% || Modulus\n"
        << "^ || Power\n"
        << "$ || Square Root\n"
        << "s || Sine\n"
        << "c || Cosine\n"
        << "t || Tangent\n"
        << "- || Negative Number\n"
        << "Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23))\n";
    // ((sin(-4^5)*1.4)/(sqrt(23+2)--2.8))*(cos(1%2)/(7.28*.1987)^(tan(23)))
}// end of displayDirections
 
std::string convertInfixToPostfix(std::string infix) {
// this function converts an infix expression to postfix
        // declare function variables
    std::string postfix;
    std::stack<char> charStack;
 
    // remove all whitespace from the string
    infix.erase(std::remove_if(infix.begin(), infix.end(), [](char c) {
        return std::isspace(static_cast<unsigned char>(c));
    }), infix.end());
 
    // negate equations marked with '--'
    infix = replaceAll(infix, "(--", "(");
 
    // automatically convert negative numbers to have the ~ symbol.
    // this is done so we can distinguish negative numbers and the subtraction symbol
    for (unsigned x = 0; x < infix.length(); ++x) {
        if (infix[x] != '-') {
            continue;
        }
        if (x == 0 || infix[x - 1] == '(' || isMathOperator(infix[x - 1])) {
            infix[x] = '~';
        }
    }
 
    // loop thru array until there is no more data
    for (unsigned x = 0; x < infix.length(); ++x) {
        // place numbers (standard, decimal, & negative)
        // numbers onto the 'postfix' string
        if (isNumeric(infix[x])) {
            if (postfix.length() > 0 && !isNumeric(postfix.back())) {
                if (!std::isspace(postfix.back())) {
                    postfix += " ";
                }
            }
            postfix += infix[x];
 
        } else if (std::isspace(infix[x])) {
            continue;
 
        } else if (isMathOperator(infix[x])) {
            if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                postfix += " ";
            }
            // use the 'orderOfOperations' function to check equality
            // of the math operator at the top of the stack compared to
            // the current math operator in the infix string
            while ((!charStack.empty()) &&
                (orderOfOperations(charStack.top()) >= orderOfOperations(infix[x]))) {
                // place the math operator from the top of the
                // stack onto the postfix string and continue the
                // process until complete
                if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                    postfix += " ";
                }
                postfix += charStack.top();
                charStack.pop();
            }
            // push the remaining math operator onto the stack
            charStack.push(infix[x]);
        }
        // push outer parentheses onto stack
        else if (infix[x] == '(') {
            charStack.push(infix[x]);
 
        } else if (infix[x] == ')') {
            // pop the current math operator from the stack
            while ((!charStack.empty()) && (charStack.top() != '(')) {
                if (postfix.length() > 0 && !std::isspace(postfix.back())) {
                    postfix += " ";
                }
                // place the math operator onto the postfix string
                postfix += charStack.top();
                // pop the next operator from the stack and
                // continue the process until complete
                charStack.pop();
            }
 
            // pop '(' symbol off the stack
            if (!charStack.empty()) {
                charStack.pop();
            } else {
                // no matching '('
                throw std::invalid_argument{ "PARENTHESES MISMATCH" };
            }
        } else {
            throw std::invalid_argument{ "INVALID INPUT" };
        }
    }
 
    // place any remaining math operators from the stack onto
    // the postfix array
    while (!charStack.empty()) {
        if (charStack.top() == '(' || charStack.top() == ')') {
            throw std::invalid_argument{ "PARENTHESES MISMATCH" };
        }
        if (postfix.length() > 0 && !std::isspace(postfix.back())) {
            postfix += " ";
        }
        postfix += charStack.top();
        charStack.pop();
    }
 
    // replace all '~' symbols with a minus sign
    postfix = replaceAll(postfix, "~", "-");
 
    return postfix;
}// end of convertInfixToPostfix
 
bool isMathOperator(char token) {
// this function checks if operand is a math operator
    switch (std::tolower(token)) {
        case '+': case '-': case '*': case '/':
        case '%': case '^': case '$': case 'c':
        case 's': case 't':
            return true;
            break;
        default:
            return false;
            break;
    }
}// end of isMathOperator
 
int orderOfOperations(char token) {
// this function returns the priority of each math operator
    int priority = 0;
    switch (std::tolower(token)) {
        case 'c': case 's': case 't':
            priority = 5;
            break;
        case '^': case '$':
            priority = 4;
            break;
        case '*': case '/': case '%':
            priority = 3;
            break;
        case '-':
            priority = 2;
            break;
        case '+':
            priority = 1;
            break;
    }
    return priority;
}// end of orderOfOperations
 
double evaluatePostfix(const std::string& postfix) {
// this function evaluates a postfix expression
    // declare function variables
    double answer = 0;
    std::stack<double> doubleStack;
 
    // split string into tokens to isolate multi digit, negative and decimal
    // numbers, aswell as single digit numbers and math operators
    auto tokens = split(postfix);
 
    // display the found tokens to the screen
    //for (unsigned x = 0; x < tokens.size(); ++x) {
    //    std::cout<< tokens.at(x) << std::endl;
    //}
 
    std::cout << "\nCalculations:\n";
 
    // loop thru array until there is no more data
    for (unsigned x = 0; x < tokens.size(); ++x) {
        auto token = tokens[x];
 
        // push numbers & negative numbers onto the stack
        if (isNumeric(token)) {
            doubleStack.push(std::atof(token.c_str()));
        }
        // if expression is a math operator, pop numbers from stack
        // & send the popped numbers to the 'calculate' function
        else if (isMathOperator(token[0]) && (!doubleStack.empty())) {
            double value1 = 0;
            double value2 = 0;
            char mathOperator = static_cast<unsigned char>(std::tolower(token[0]));
 
            // if expression is square root, sin, cos,
            // or tan operation only pop stack once
            if (mathOperator == '$' || mathOperator == 's' || mathOperator == 'c' || mathOperator == 't') {
                value2 = 0;
                value1 = doubleStack.top();
                doubleStack.pop();
                answer = calculate(mathOperator, value1, value2);
                doubleStack.push(answer);
 
            } else if (doubleStack.size() > 1) {
                value2 = doubleStack.top();
                doubleStack.pop();
                value1 = doubleStack.top();
                doubleStack.pop();
                answer = calculate(mathOperator, value1, value2);
                doubleStack.push(answer);
            }
        } else {
            // this should never execute, & if it does, something went really wrong
            throw std::invalid_argument{ "INVALID POSTFIX STRING" };
        }
    }
    // pop the final answer from the stack, and return to main
    if (!doubleStack.empty()) {
        answer = doubleStack.top();
    }
    return answer;
}// end of evaluatePostfix
 
double calculate(char mathOperator, double value1, double value2) {
// this function carries out the actual math process
    double ans = 0;
    switch (std::tolower(mathOperator)) {
        case '+':
            std::cout << value1 << mathOperator << value2;
            ans = value1 + value2;
            break;
        case '-':
            std::cout << value1 << mathOperator << value2;
            ans = value1 - value2;
            break;
        case '*':
            std::cout << value1 << mathOperator << value2;
            ans = value1 * value2;
            break;
        case '/':
            std::cout << value1 << mathOperator << value2;
            ans = value1 / value2;
            break;
        case '%':
            std::cout << value1 << mathOperator << value2;
            ans = ((int)value1 % (int)value2) + std::modf(value1, &value2);
            break;
        case '^':
            std::cout << value1 << mathOperator << value2;
            ans = std::pow(value1, value2);
            break;
        case '$':
            std::cout << char(251) << value1;
            ans = std::sqrt(value1);
            break;
        case 'c':
            std::cout << "cos(" << value1 << ")";
            ans = std::cos(value1);
            break;
        case 's':
            std::cout << "sin(" << value1 << ")";
            ans = std::sin(value1);
            break;
        case 't':
            std::cout << "tan(" << value1 << ")";
            ans = std::tan(value1);
            break;
        default:
            ans = 0;
            break;
    }
    std::cout << " = " << ans << std::endl;
    return ans;
}// end of calculate
 
std::vector<std::string> split(const std::string& source, const std::string& delimiters) {
    std::size_t prev = 0;
    std::size_t currentPos = 0;
    std::vector<std::string> results;
 
    while ((currentPos = source.find_first_of(delimiters, prev)) != std::string::npos) {
        if (currentPos > prev) {
            results.push_back(source.substr(prev, currentPos - prev));
        }
        prev = currentPos + 1;
    }
    if (prev < source.length()) {
        results.push_back(source.substr(prev, std::string::npos));
    }
    return results;
}// end of split
 
std::string replaceAll(const std::string& source
    , const std::string& oldValue, const std::string& newValue) {
    if (oldValue.empty()) {
        return source;
    }
    std::string newString;
    newString.reserve(source.length());
    std::size_t lastPos = 0;
    std::size_t findPos;
    while (std::string::npos != (findPos = source.find(oldValue, lastPos))) {
        newString.append(source, lastPos, findPos - lastPos);
        newString += newValue;
        lastPos = findPos + oldValue.length();
    }
    newString += source.substr(lastPos);
    return newString;
}// end of replaceAll
 
bool isNumeric(char value) {
    return std::isdigit(value) || value == '.' || value == '~';
}// end of isNumeric
 
bool isNumeric(std::string value) {
    for (unsigned index = 0; index < value.length(); ++index) {
        if (index == 0 && value[index] == '-' && value.length() > 1) {
            continue;
        }
        if (!isNumeric(value[index])) {
            return false;
        }
    }
    return true;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

The following is sample output.

====== RUN 1 ======
==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: 12/3*9 The Infix expression = 12/3*9 The Postfix expression = 12 3 / 9 * Calculations: 12/3 = 4 4*9 = 36 Final answer = 36 ====== RUN 2 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: -150.89996 - 87.56643 The Infix expression = -150.89996 - 87.56643 The Postfix expression = -150.89996 87.56643 - Calculations: -150.9-87.5664 = -238.466 Final answer = -238.466 ====== RUN 3 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) The Infix expression = ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) The Postfix expression = -4 5 ^ s 1.4 * 23 2 + $ -2.8 - / 1 2 % c 7.28 .1987 * 23 t ^ / * Calculations: -4^5 = -1024 sin(-1024) = 0.158533 0.158533*1.4 = 0.221947 23+2 = 25 √25 = 5 5--2.8 = 7.8 0.221947/7.8 = 0.0284547 1%2 = 1 cos(1) = 0.540302 7.28*0.1987 = 1.44654 tan(23) = 1.58815 1.44654^1.58815 = 1.79733 0.540302/1.79733 = 0.300614 0.0284547*0.300614 = 0.00855389 Final answer = 0.00855389 ====== RUN 4 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: (1987 + 1991) * -1 The Infix expression = (1987 + 1991) * -1 The Postfix expression = 1987 1991 + -1 * Calculations: 1987+1991 = 3978 3978*-1 = -3978 Final answer = -3978 ====== RUN 5 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: (1+(2*((3+(4*5))*6))) The Infix expression = (1+(2*((3+(4*5))*6))) The Postfix expression = 1 2 3 4 5 * + 6 * * + Calculations: 4*5 = 20 3+20 = 23 23*6 = 138 2*138 = 276 1+276 = 277 Final answer = 277

C++ || Multi Digit, Decimal & Negative Number Infix To Postfix Conversion & Evaluation

January 31, 2014 admin 1 Comment

Click Here For Updated Version Of Program

The following is sample code which demonstrates the implementation of a multi digit, decimal, and negative number infix to postfix converter and evaluator using a Finite State Machine

REQUIRED KNOWLEDGE FOR THIS PROGRAM

How To Convert Infix To Postfix How To Evaluate A Postfix Expression What Is A Finite State Machine?

Using a Finite State Machine, the program demonstrated on this page has the ability to convert and evaluate a single digit, multi digit, decimal number, and/or negative number infix equation. So for example, if the the infix equation of (19.87 * -2) was entered into the program, the converted postfix expression of 19.87 ~2* would display to the screen, as well as the final evaluated answer of -39.74.

NOTE: In this program, negative numbers are represented by the “~” symbol on the postfix string. This is used to differentiate between a negative number and a subtraction symbol.

This program has the following flow of control:

• Get an infix expression from the user • Convert the infix expression to postfix • Use a Finite State Machine to isolate all of the math operators, multi digit, decimal, negative and single digit numbers that are found in the postfix expression • Evaluate the postfix expression using the tokens found from the above step • Display the evaluated answer to the screen

The above steps are implemented below.





		
		
			Multi Digit Infix To Postfix Conversion & Evaluation
			
C++
			
			// ============================================================================
//   Author:  Kenneth Perkins
//   Taken From: http://programmingnotes.org/
//   Date:  Jan 31, 2014
//   File: InToPostEval.cpp
//   Description: The following demonstrates the implementation of an infix to
//     postfix converter and evaluator. Using a Finite State Machine, this
//     program has the ability to convert and evaluate multi digit, decimal,
//     negative and positive values.
// ============================================================================
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <stack>
#include <algorithm>
using namespace std;

/* This holds the transition states for our Finite State Machine
    -- They are placed in numerical order for easy understanding within
        the FSM array, which is located below */

enum FSM_TRANSITIONS
{
    REJECT = 0,
    INTEGER,
    REAL,
    NEGATIVE,
    OPERATOR,
    UNKNOWN,
    SPACE
};

/* This is the Finite State Machine
    -- The zero represents a place holder, so the row in the array
            starts on row 1 instead of 0

                           integer,  real,  negative, operator, unknown, space */
int stateTable[][7] = { {0, INTEGER,  REAL, NEGATIVE, OPERATOR,  UNKNOWN,  SPACE},
/* STATE 1 */   {INTEGER,  INTEGER,  REAL,   REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 2 */   {REAL,       REAL,  REJECT,  REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 3 */   {NEGATIVE, INTEGER,  REAL,   REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 4 */   {OPERATOR,  REJECT, REJECT,  REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 5 */   {UNKNOWN,   REJECT, REJECT,  REJECT,  REJECT,   UNKNOWN, REJECT},
/* STATE 6 */   {SPACE,     REJECT, REJECT,  REJECT,  REJECT,   REJECT,  REJECT} };

// function prototypes
void DisplayDirections();
string ConvertInfixToPostfix(string infix);
bool IsMathOperator(char token);
int OrderOfOperations(char token);
vector<string> Lexer(string postfix);
int Get_FSM_Col(char& currentChar);
double EvaluatePostfix(const vector<string>& postfix);
double Calculate(char token, double op1, double op2);

int main()
{
    // declare variables
    string infix = "";
    string postfix = "";
    double answer = 0;
    vector<string> tokens;

    // display directions to user
    DisplayDirections();

    // get data from user
    cout << "\nPlease enter an Infix expression: ";
    getline(cin, infix);

    postfix = ConvertInfixToPostfix(infix);

    // use the "Lexer" function to isolate multi digit, negative and decimal
    // numbers, aswell as single digit numbers and math operators
    tokens = Lexer(postfix);

    // display the found tokens to the screen
    //for (unsigned x = 0; x < tokens.size(); ++x)
    //{
    //    cout<<tokens.at(x)<<endl;
    //}

    cout << "\nThe Infix expression = " << infix;
    cout << "\nThe Postfix expression = " << postfix << endl;

    answer = EvaluatePostfix(tokens);

    cout << "\nFinal answer = " << answer << endl;

    cin.get();
    return 0;
}// end of main

void DisplayDirections()
{// this function displays instructions to the screen
    cout << "\n==== Infix To Postfix Conversion & Evaluation ====\n"
        << "\nMath Operators:\n"
        << "+ || Addition\n"
        << "- || Subtraction\n"
        << "* || Multiplication\n"
        << "/ || Division\n"
        << "% || Modulus\n"
        << "^ || Power\n"
        << "$ || Square Root\n"
        << "s || Sine\n"
        << "c || Cosine\n"
        << "t || Tangent\n"
        << "- || Negative Number\n"
        << "Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23))\n";
    // ((sin(-4^5)*1.4)/(sqrt(23+2)--2.8))*(cos(1%2)/(7.28*.1987)^(tan(23)))
}// end of DisplayDirections

string ConvertInfixToPostfix(string infix)
{// this function converts an infix expression to postfix
    // declare function variables
    string postfix;
    stack<char> charStack;

    // remove all whitespace from the string
    infix.erase(std::remove_if(infix.begin(), infix.end(), [](char c) {
        return std::isspace(static_cast<unsigned char>(c));
    }), infix.end());

    // automatically convert negative numbers to have the ~ symbol
    for (unsigned x = 0; x < infix.length(); ++x) {
        if (infix[x] != '-') {
            continue;
        } else if (x + 1 < infix.length() && IsMathOperator(infix[x + 1])) {
            continue;
        }
        if (x == 0 || infix[x - 1] == '(' || IsMathOperator(infix[x - 1])) {
            infix[x] = '~';
        }
    }

    // loop thru array until there is no more data
    for (unsigned x = 0; x < infix.length(); ++x)
    {
        // place numbers (standard, decimal, & negative)
        // numbers onto the 'postfix' string
        if ((isdigit(infix[x])) || (infix[x] == '.') || (infix[x] == '~'))
        {
            postfix += infix[x];
        }
        else if (isspace(infix[x]))
        {
            continue;
        }
        else if (IsMathOperator(infix[x]))
        {
            postfix += " ";
            // use the 'OrderOfOperations' function to check equality
            // of the math operator at the top of the stack compared to
            // the current math operator in the infix string
            while ((!charStack.empty()) &&
                (OrderOfOperations(charStack.top()) >= OrderOfOperations(infix[x])))
            {
                // place the math operator from the top of the
                // stack onto the postfix string and continue the
                // process until complete
                postfix += charStack.top();
                charStack.pop();
            }
            // push the remaining math operator onto the stack
            charStack.push(infix[x]);
        }
        // push outer parentheses onto stack
        else if (infix[x] == '(')
        {
            charStack.push(infix[x]);
        }
        else if (infix[x] == ')')
        {
            // pop the current math operator from the stack
            while ((!charStack.empty()) && (charStack.top() != '('))
            {
                // place the math operator onto the postfix string
                postfix += charStack.top();
                // pop the next operator from the stack and
                // continue the process until complete
                charStack.pop();
            }

            if (!charStack.empty()) // pop '(' symbol off the stack
            {
                charStack.pop();
            }
            else // no matching '('
            {
                cout << "\nPARENTHESES MISMATCH #1\n";
                exit(1);
            }
        }
        else
        {
            cout << "\nINVALID INPUT #1\n";
            exit(1);
        }
    }

    // place any remaining math operators from the stack onto
    // the postfix array
    while (!charStack.empty())
    {
        postfix += charStack.top();
        charStack.pop();
    }

    return postfix;
}// end of ConvertInfixToPostfix

bool IsMathOperator(char token)
{// this function checks if operand is a math operator
    switch (tolower(token))
    {
    case '+': case '-': case '*': case '/':
    case '%': case '^': case '$': case 'c':
    case 's': case 't':
        return true;
        break;
    default:
        return false;
        break;
    }
}// end of IsMathOperator

int OrderOfOperations(char token)
{// this function returns the priority of each math operator
    int priority = 0;
    switch (tolower(token))
    {
    case 'c': case 's': case 't':
        priority = 5;
        break;
    case '^': case '$':
        priority = 4;
        break;
    case '*': case '/': case '%':
        priority = 3;
        break;
    case '-':
        priority = 2;
        break;
    case '+':
        priority = 1;
        break;
    }
    return priority;
}// end of OrderOfOperations

vector<string> Lexer(string postfix)
{// this function parses a postfix string using an FSM to generate
 //  each individual token in the expression
    vector<string> tokens;
    char currentChar = ' ';
    int col = REJECT;
    int currentState = REJECT;
    string currentToken = "";

    // use an FSM to parse multidigit and decimal numbers
    // also does error check for invalid input of decimals
    for (unsigned x = 0; x < postfix.length();)
    {
        currentChar = postfix[x];

        // get the column number for the current character
        col = Get_FSM_Col(currentChar);

        // exit if the real number has multiple periods "."
        // in the expression (i.e: 19.3427.23)
        if ((currentState == REAL) && (col == REAL))
        {
            cerr << "\nINVALID INPUT #2\n";
            exit(1);
        }
        /* ========================================================

            THIS IS WHERE WE CHECK THE FINITE STATE MACHINE TABLE
               USING THE "col" VARIABLE FROM ABOVE ^

          ========================================================= */

          // get the current state of our machine
        currentState = stateTable[currentState][col];

        /* ===================================================

          THIS IS WHERE WE CHECK FOR A SUCCESSFUL PARSE
           - If the current state in our machine == REJECT
             (the starting state), then we have successfully parsed
             a token, which is returned to its caller

            - ELSE we continue trying to find a successful token

            =================================================== */
        if (currentState == REJECT)
        {
            if (currentToken != " ") // we dont care about whitespace
            {
                tokens.push_back(currentToken);
            }
            currentToken = "";
        }
        else
        {
            currentToken += currentChar;
            ++x;
        }

    }
    // this ensures the last token gets saved when
    // we reach the end of the postfix string buffer
    if (currentToken != " ") // we dont care about whitespace
    {
        tokens.push_back(currentToken);
    }
    return tokens;
}// end of Lexer

int Get_FSM_Col(char& currentChar)
{// this function determines the state of the type of character being examined
    // check for whitespace
    if (isspace(currentChar))
    {
        return SPACE;
    }

    // check for integer numbers
    else if (isdigit(currentChar))
    {
        return INTEGER;
    }

    // check for real numbers
    else if (currentChar == '.')
    {
        return REAL;
    }

    // check for negative numbers
    else if (currentChar == '~')
    {
        currentChar = '-';
        return NEGATIVE;
    }

    // check for math operators
    else if (IsMathOperator(currentChar))
    {
        return OPERATOR;
    }
    return UNKNOWN;
}// end of Get_FSM_Col

double EvaluatePostfix(const vector<string>& postfix)
{// this function evaluates a postfix expression
    // declare function variables
    double op1 = 0;
    double op2 = 0;
    double answer = 0;
    stack<double> doubleStack;

    cout << "\nCalculations:\n";

    // loop thru array until there is no more data
    for (unsigned x = 0; x < postfix.size(); ++x)
    {
        // push numbers onto the stack
        if ((isdigit(postfix[x][0])) || (postfix[x][0] == '.'))
        {
            doubleStack.push(atof(postfix[x].c_str()));
        }
        // push negative numbers onto the stack
        else if ((postfix[x].length() > 1) && ((postfix[x][0] == '-') &&
            (isdigit(postfix[x][1]) || (postfix[x][1] == '.'))))
        {
            doubleStack.push(atof(postfix[x].c_str()));
        }
        // if expression is a math operator, pop numbers from stack
        // & send the popped numbers to the 'Calculate' function
        else if (IsMathOperator(postfix[x][0]) && (!doubleStack.empty()))
        {
            char token = tolower(postfix[x][0]);

            // if expression is square root, sin, cos,
            // or tan operation only pop stack once
            if (token == '$' || token == 's' || token == 'c' || token == 't')
            {
                op2 = 0;
                op1 = doubleStack.top();
                doubleStack.pop();
                answer = Calculate(token, op1, op2);
                doubleStack.push(answer);
            }
            else if (doubleStack.size() > 1)
            {
                op2 = doubleStack.top();
                doubleStack.pop();
                op1 = doubleStack.top();
                doubleStack.pop();
                answer = Calculate(token, op1, op2);
                doubleStack.push(answer);
            }
        }
        else // this should never execute, & if it does, something went really wrong
        {
            cout << "\nINVALID INPUT #3\n";
            exit(1);
        }
    }
    // pop the final answer from the stack, and return to main
    if (!doubleStack.empty())
    {
        answer = doubleStack.top();
    }
    return answer;
}// end of EvaluatePostfix

double Calculate(char token, double op1, double op2)
{// this function carries out the actual math process
    double ans = 0;
    switch (tolower(token))
    {
    case '+':
        cout << op1 << token << op2 << " = ";
        ans = op1 + op2;
        break;
    case '-':
        cout << op1 << token << op2 << " = ";
        ans = op1 - op2;
        break;
    case '*':
        cout << op1 << token << op2 << " = ";
        ans = op1 * op2;
        break;
    case '/':
        cout << op1 << token << op2 << " = ";
        ans = op1 / op2;
        break;
    case '%':
        cout << op1 << token << op2 << " = ";
        ans = ((int)op1 % (int)op2) + modf(op1, &op2);
        break;
    case '^':
        cout << op1 << token << op2 << " = ";
        ans = pow(op1, op2);
        break;
    case '$':
        cout << char(251) << op1 << " = ";
        ans = sqrt(op1);
        break;
    case 'c':
        cout << "cos(" << op1 << ") = ";
        ans = cos(op1);
        break;
    case 's':
        cout << "sin(" << op1 << ") = ";
        ans = sin(op1);
        break;
    case 't':
        cout << "tan(" << op1 << ") = ";
        ans = tan(op1);
        break;
    default:
        ans = 0;
        break;
    }
    cout << ans << endl;
    return ans;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//   Author:  Kenneth Perkins
//   Taken From: http://programmingnotes.org/
//   Date:  Jan 31, 2014
//   File: InToPostEval.cpp
//   Description: The following demonstrates the implementation of an infix to
//     postfix converter and evaluator. Using a Finite State Machine, this
//     program has the ability to convert and evaluate multi digit, decimal,
//     negative and positive values.
// ============================================================================
#include <iostream>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <stack>
#include <algorithm>
using namespace std;
 
/* This holds the transition states for our Finite State Machine
    -- They are placed in numerical order for easy understanding within
        the FSM array, which is located below */
 
enum FSM_TRANSITIONS
{
    REJECT = 0,
    INTEGER,
    REAL,
    NEGATIVE,
    OPERATOR,
    UNKNOWN,
    SPACE
};
 
/* This is the Finite State Machine
    -- The zero represents a place holder, so the row in the array
            starts on row 1 instead of 0
 
                           integer,  real,  negative, operator, unknown, space */
int stateTable[][7] = { {0, INTEGER,  REAL, NEGATIVE, OPERATOR,  UNKNOWN,  SPACE},
/* STATE 1 */   {INTEGER,  INTEGER,  REAL,   REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 2 */   {REAL,       REAL,  REJECT,  REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 3 */   {NEGATIVE, INTEGER,  REAL,   REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 4 */   {OPERATOR,  REJECT, REJECT,  REJECT,  REJECT,   REJECT,  REJECT},
/* STATE 5 */   {UNKNOWN,   REJECT, REJECT,  REJECT,  REJECT,   UNKNOWN, REJECT},
/* STATE 6 */   {SPACE,     REJECT, REJECT,  REJECT,  REJECT,   REJECT,  REJECT} };
 
// function prototypes
void DisplayDirections();
string ConvertInfixToPostfix(string infix);
bool IsMathOperator(char token);
int OrderOfOperations(char token);
vector<string> Lexer(string postfix);
int Get_FSM_Col(char& currentChar);
double EvaluatePostfix(const vector<string>& postfix);
double Calculate(char token, double op1, double op2);
 
int main()
{
    // declare variables
    string infix = "";
    string postfix = "";
    double answer = 0;
    vector<string> tokens;
 
    // display directions to user
    DisplayDirections();
 
    // get data from user
    cout << "\nPlease enter an Infix expression: ";
    getline(cin, infix);
 
    postfix = ConvertInfixToPostfix(infix);
 
    // use the "Lexer" function to isolate multi digit, negative and decimal
    // numbers, aswell as single digit numbers and math operators
    tokens = Lexer(postfix);
 
    // display the found tokens to the screen
    //for (unsigned x = 0; x < tokens.size(); ++x)
    //{
    //    cout<<tokens.at(x)<<endl;
    //}
 
    cout << "\nThe Infix expression = " << infix;
    cout << "\nThe Postfix expression = " << postfix << endl;
 
    answer = EvaluatePostfix(tokens);
 
    cout << "\nFinal answer = " << answer << endl;
 
    cin.get();
    return 0;
}// end of main
 
void DisplayDirections()
{// this function displays instructions to the screen
    cout << "\n==== Infix To Postfix Conversion & Evaluation ====\n"
        << "\nMath Operators:\n"
        << "+ || Addition\n"
        << "- || Subtraction\n"
        << "* || Multiplication\n"
        << "/ || Division\n"
        << "% || Modulus\n"
        << "^ || Power\n"
        << "$ || Square Root\n"
        << "s || Sine\n"
        << "c || Cosine\n"
        << "t || Tangent\n"
        << "- || Negative Number\n"
        << "Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23))\n";
    // ((sin(-4^5)*1.4)/(sqrt(23+2)--2.8))*(cos(1%2)/(7.28*.1987)^(tan(23)))
}// end of DisplayDirections
 
string ConvertInfixToPostfix(string infix)
{// this function converts an infix expression to postfix
    // declare function variables
    string postfix;
    stack<char> charStack;
 
    // remove all whitespace from the string
    infix.erase(std::remove_if(infix.begin(), infix.end(), [](char c) {
        return std::isspace(static_cast<unsigned char>(c));
    }), infix.end());
 
    // automatically convert negative numbers to have the ~ symbol
    for (unsigned x = 0; x < infix.length(); ++x) {
        if (infix[x] != '-') {
            continue;
        } else if (x + 1 < infix.length() && IsMathOperator(infix[x + 1])) {
            continue;
        }
        if (x == 0 || infix[x - 1] == '(' || IsMathOperator(infix[x - 1])) {
            infix[x] = '~';
        }
    }
 
    // loop thru array until there is no more data
    for (unsigned x = 0; x < infix.length(); ++x)
    {
        // place numbers (standard, decimal, & negative)
        // numbers onto the 'postfix' string
        if ((isdigit(infix[x])) || (infix[x] == '.') || (infix[x] == '~'))
        {
            postfix += infix[x];
        }
        else if (isspace(infix[x]))
        {
            continue;
        }
        else if (IsMathOperator(infix[x]))
        {
            postfix += " ";
            // use the 'OrderOfOperations' function to check equality
            // of the math operator at the top of the stack compared to
            // the current math operator in the infix string
            while ((!charStack.empty()) &&
                (OrderOfOperations(charStack.top()) >= OrderOfOperations(infix[x])))
            {
                // place the math operator from the top of the
                // stack onto the postfix string and continue the
                // process until complete
                postfix += charStack.top();
                charStack.pop();
            }
            // push the remaining math operator onto the stack
            charStack.push(infix[x]);
        }
        // push outer parentheses onto stack
        else if (infix[x] == '(')
        {
            charStack.push(infix[x]);
        }
        else if (infix[x] == ')')
        {
            // pop the current math operator from the stack
            while ((!charStack.empty()) && (charStack.top() != '('))
            {
                // place the math operator onto the postfix string
                postfix += charStack.top();
                // pop the next operator from the stack and
                // continue the process until complete
                charStack.pop();
            }
 
            if (!charStack.empty()) // pop '(' symbol off the stack
            {
                charStack.pop();
            }
            else // no matching '('
            {
                cout << "\nPARENTHESES MISMATCH #1\n";
                exit(1);
            }
        }
        else
        {
            cout << "\nINVALID INPUT #1\n";
            exit(1);
        }
    }
 
    // place any remaining math operators from the stack onto
    // the postfix array
    while (!charStack.empty())
    {
        postfix += charStack.top();
        charStack.pop();
    }
 
    return postfix;
}// end of ConvertInfixToPostfix
 
bool IsMathOperator(char token)
{// this function checks if operand is a math operator
    switch (tolower(token))
    {
    case '+': case '-': case '*': case '/':
    case '%': case '^': case '$': case 'c':
    case 's': case 't':
        return true;
        break;
    default:
        return false;
        break;
    }
}// end of IsMathOperator
 
int OrderOfOperations(char token)
{// this function returns the priority of each math operator
    int priority = 0;
    switch (tolower(token))
    {
    case 'c': case 's': case 't':
        priority = 5;
        break;
    case '^': case '$':
        priority = 4;
        break;
    case '*': case '/': case '%':
        priority = 3;
        break;
    case '-':
        priority = 2;
        break;
    case '+':
        priority = 1;
        break;
    }
    return priority;
}// end of OrderOfOperations
 
vector<string> Lexer(string postfix)
{// this function parses a postfix string using an FSM to generate
 //  each individual token in the expression
    vector<string> tokens;
    char currentChar = ' ';
    int col = REJECT;
    int currentState = REJECT;
    string currentToken = "";
 
    // use an FSM to parse multidigit and decimal numbers
    // also does error check for invalid input of decimals
    for (unsigned x = 0; x < postfix.length();)
    {
        currentChar = postfix[x];
 
        // get the column number for the current character
        col = Get_FSM_Col(currentChar);
 
        // exit if the real number has multiple periods "."
        // in the expression (i.e: 19.3427.23)
        if ((currentState == REAL) && (col == REAL))
        {
            cerr << "\nINVALID INPUT #2\n";
            exit(1);
        }
        /* ========================================================
 
            THIS IS WHERE WE CHECK THE FINITE STATE MACHINE TABLE
               USING THE "col" VARIABLE FROM ABOVE ^
 
          ========================================================= */
 
          // get the current state of our machine
        currentState = stateTable[currentState][col];
 
        /* ===================================================
 
          THIS IS WHERE WE CHECK FOR A SUCCESSFUL PARSE
           - If the current state in our machine == REJECT
             (the starting state), then we have successfully parsed
             a token, which is returned to its caller
 
            - ELSE we continue trying to find a successful token
 
            =================================================== */
        if (currentState == REJECT)
        {
            if (currentToken != " ") // we dont care about whitespace
            {
                tokens.push_back(currentToken);
            }
            currentToken = "";
        }
        else
        {
            currentToken += currentChar;
            ++x;
        }
 
    }
    // this ensures the last token gets saved when
    // we reach the end of the postfix string buffer
    if (currentToken != " ") // we dont care about whitespace
    {
        tokens.push_back(currentToken);
    }
    return tokens;
}// end of Lexer
 
int Get_FSM_Col(char& currentChar)
{// this function determines the state of the type of character being examined
    // check for whitespace
    if (isspace(currentChar))
    {
        return SPACE;
    }
 
    // check for integer numbers
    else if (isdigit(currentChar))
    {
        return INTEGER;
    }
 
    // check for real numbers
    else if (currentChar == '.')
    {
        return REAL;
    }
 
    // check for negative numbers
    else if (currentChar == '~')
    {
        currentChar = '-';
        return NEGATIVE;
    }
 
    // check for math operators
    else if (IsMathOperator(currentChar))
    {
        return OPERATOR;
    }
    return UNKNOWN;
}// end of Get_FSM_Col
 
double EvaluatePostfix(const vector<string>& postfix)
{// this function evaluates a postfix expression
    // declare function variables
    double op1 = 0;
    double op2 = 0;
    double answer = 0;
    stack<double> doubleStack;
 
    cout << "\nCalculations:\n";
 
    // loop thru array until there is no more data
    for (unsigned x = 0; x < postfix.size(); ++x)
    {
        // push numbers onto the stack
        if ((isdigit(postfix[x][0])) || (postfix[x][0] == '.'))
        {
            doubleStack.push(atof(postfix[x].c_str()));
        }
        // push negative numbers onto the stack
        else if ((postfix[x].length() > 1) && ((postfix[x][0] == '-') &&
            (isdigit(postfix[x][1]) || (postfix[x][1] == '.'))))
        {
            doubleStack.push(atof(postfix[x].c_str()));
        }
        // if expression is a math operator, pop numbers from stack
        // & send the popped numbers to the 'Calculate' function
        else if (IsMathOperator(postfix[x][0]) && (!doubleStack.empty()))
        {
            char token = tolower(postfix[x][0]);
 
            // if expression is square root, sin, cos,
            // or tan operation only pop stack once
            if (token == '$' || token == 's' || token == 'c' || token == 't')
            {
                op2 = 0;
                op1 = doubleStack.top();
                doubleStack.pop();
                answer = Calculate(token, op1, op2);
                doubleStack.push(answer);
            }
            else if (doubleStack.size() > 1)
            {
                op2 = doubleStack.top();
                doubleStack.pop();
                op1 = doubleStack.top();
                doubleStack.pop();
                answer = Calculate(token, op1, op2);
                doubleStack.push(answer);
            }
        }
        else // this should never execute, & if it does, something went really wrong
        {
            cout << "\nINVALID INPUT #3\n";
            exit(1);
        }
    }
    // pop the final answer from the stack, and return to main
    if (!doubleStack.empty())
    {
        answer = doubleStack.top();
    }
    return answer;
}// end of EvaluatePostfix
 
double Calculate(char token, double op1, double op2)
{// this function carries out the actual math process
    double ans = 0;
    switch (tolower(token))
    {
    case '+':
        cout << op1 << token << op2 << " = ";
        ans = op1 + op2;
        break;
    case '-':
        cout << op1 << token << op2 << " = ";
        ans = op1 - op2;
        break;
    case '*':
        cout << op1 << token << op2 << " = ";
        ans = op1 * op2;
        break;
    case '/':
        cout << op1 << token << op2 << " = ";
        ans = op1 / op2;
        break;
    case '%':
        cout << op1 << token << op2 << " = ";
        ans = ((int)op1 % (int)op2) + modf(op1, &op2);
        break;
    case '^':
        cout << op1 << token << op2 << " = ";
        ans = pow(op1, op2);
        break;
    case '$':
        cout << char(251) << op1 << " = ";
        ans = sqrt(op1);
        break;
    case 'c':
        cout << "cos(" << op1 << ") = ";
        ans = cos(op1);
        break;
    case 's':
        cout << "sin(" << op1 << ") = ";
        ans = sin(op1);
        break;
    case 't':
        cout << "tan(" << op1 << ") = ";
        ans = tan(op1);
        break;
    default:
        ans = 0;
        break;
    }
    cout << ans << endl;
    return ans;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

The following is sample output.

====== RUN 1 ====== ==== Infix To Postfix Conversion & Evaluation ====
Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent ~ || Negative Number Sample Infix Equation: ((s(~4^5)*1.4)/($(23+2)-~2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: 12/3*9 The Infix expression = 12/3*9 The Postfix expression = 12 3 /9* Calculations: 12/3 = 4 4*9 = 36 Final answer = 36 ====== RUN 2 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent ~ || Negative Number Sample Infix Equation: ((s(~4^5)*1.4)/($(23+2)-~2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: -150.89996 - 87.56643 The Infix expression = -150.89996 - 87.56643 The Postfix expression = ~150.89996 87.56643- Calculations: -150.9-87.5664 = -238.466 Final answer = -238.466 ====== RUN 3 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent ~ || Negative Number Sample Infix Equation: ((s(~4^5)*1.4)/($(23+2)-~2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: ((s(~4^5)*1.4)/($(23+2)-~2.8))*(c(1%2)/(7.28*.1987)^(t23)) The Infix expression = ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) The Postfix expression = ~4 5^ s1.4* 23 2+ $~2.8-/ 1 2% c7.28 .1987* 23t^/* Calculations: -4^5 = -1024 sin(-1024) = 0.158533 0.158533*1.4 = 0.221947 23+2 = 25 √25 = 5 5--2.8 = 7.8 0.221947/7.8 = 0.0284547 1%2 = 1 cos(1) = 0.540302 7.28*0.1987 = 1.44654 tan(23) = 1.58815 1.44654^1.58815 = 1.79733 0.540302/1.79733 = 0.300614 0.0284547*0.300614 = 0.00855389 Final answer = 0.00855389 ====== RUN 4 ====== ==== Infix To Postfix Conversion & Evaluation ==== Math Operators: + || Addition - || Subtraction * || Multiplication / || Division % || Modulus ^ || Power $ || Square Root s || Sine c || Cosine t || Tangent - || Negative Number Sample Infix Equation: ((s(-4^5)*1.4)/($(23+2)--2.8))*(c(1%2)/(7.28*.1987)^(t23)) Please enter an Infix expression: (1987 + 1991) * -1 The Infix expression = (1987 + 1991) * -1 The Postfix expression = 1987 1991+ ~1* Calculations: 1987+1991 = 3978 3978*-1 = -3978 Final answer = -3978

Python || Find The Average Using A List – Omit Highest And Lowest Scores

January 29, 2014 admin No comments

This page will consist of a program which calculates the average of a specific amount of numbers using a list.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Lists For Loops Arithmetic Operators Basic Math - How To Find The Average

The following program is fairly simple, and was used to introduce the list concept. This program prompts the user to enter the total amount of numbers they wish to find the average for, then displays the answer to the screen. Using a sort, this program also has the ability to find the average of a list of numbers, omitting the highest and lowest valued items.





		
		
			Find The Average Using A List
			
Python
			
			# =============================================================================
#   Author:  K Perkins
#   Taken From: http://programmingnotes.org/
#   Date:  Jan 29, 2014
#   File: Average.py
#   Description: The following demonstrates finding the average of numbers
#     contained in a list.
# =============================================================================
# calculate the average of numbers in a list
def Average(arry, size):
    total = 0

    # traverse the list adding all the items together
    for x in range(size):
        total += arry[x]

    # return the average
    return total / size
## end of Average

def main():
    # declare variables
    arry = [] # initialize the list
    numElems = 0

    # ask user how many items they want to place in list
    numElems = int(input("How many items do you want to place into the list?: "))

    # print a newline
    print("")

    # user enters data into list using a for loop
    for x in range(0, numElems):
        arry.append(int(input("Enter item #%d: " % (x+1))))

    # display data
    print("nThe current items inside the list are: ")
    for x in range(0, numElems):
        print("Item #%d: %d" % ((x+1), arry[x]))

    # display the average using a function
    print("nThe average of the %d numbers is %.2f" %
        (numElems, Average(arry, len(arry))))

    # sort the numbers in the list from lowest to highest
    arry.sort()

    # erase the highest/lowest numbers
    arry.pop(len(arry)-1)
    arry.pop(0)

    # display the average using a function
    print("nThe average adjusted score omitting the highest and "
        "lowest result is %.2f" % (Average(arry, len(arry))))
## end of main

if __name__ == "__main__":
    main()
# http://programmingnotes.org/
			
				
					
				
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						# =============================================================================
#   Author:  K Perkins
#   Taken From: http://programmingnotes.org/
#   Date:  Jan 29, 2014
#   File: Average.py
#   Description: The following demonstrates finding the average of numbers
#     contained in a list.
# =============================================================================
# calculate the average of numbers in a list
def Average(arry, size):
    total = 0
 
    # traverse the list adding all the items together
    for x in range(size):
        total += arry[x]
 
    # return the average
    return total / size
## end of Average
 
def main():
    # declare variables
    arry = [] # initialize the list
    numElems = 0
 
    # ask user how many items they want to place in list
    numElems = int(input("How many items do you want to place into the list?: "))
 
    # print a newline
    print("")
 
    # user enters data into list using a for loop
    for x in range(0, numElems):
        arry.append(int(input("Enter item #%d: " % (x+1))))
 
    # display data
    print("nThe current items inside the list are: ")
    for x in range(0, numElems):
        print("Item #%d: %d" % ((x+1), arry[x]))
 
    # display the average using a function
    print("nThe average of the %d numbers is %.2f" %
        (numElems, Average(arry, len(arry))))
 
    # sort the numbers in the list from lowest to highest
    arry.sort()
 
    # erase the highest/lowest numbers
    arry.pop(len(arry)-1)
    arry.pop(0)
 
    # display the average using a function
    print("nThe average adjusted score omitting the highest and "
        "lowest result is %.2f" % (Average(arry, len(arry))))
## end of main
 
if __name__ == "__main__":
    main()
# http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

The following is sample output.

How many items do you want to place into the list?: 5
Enter item #1: 7 Enter item #2: 7 Enter item #3: 4 Enter item #4: 8 Enter item #5: 7 The current items inside the list are: Item #1: 7 Item #2: 7 Item #3: 4 Item #4: 8 Item #5: 7 The average of the 5 numbers is 6.60
The average adjusted score omitting the highest and lowest result is 7.00

Python || Snippet – How To Input Numbers Into A List & Display Its Contents Back To User

May 30, 2013 admin No comments

This snippet demonstrates how to place numbers into a list. It also shows how to display the contents of the list back to the user via stdout.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Python Lists For Loops





		
		
			Insert & Display Items In A List
			
Python
			
			def main():
    # declare variables   
    arry = [] # initialize the list
    numElems = 0
    
    # ask user how many items they want to place in list
    numElems = int(input("How many items do you want to place into the list?: "))
    
    # print a newline
    print("")
    
    # user enters data into list using a for loop
    # you can also use a while loop, but for loops are more common
    # when dealing with lists
    for x in range(0, numElems):
        arry.append(int(input("Enter item #%d: " % (x+1))))
    
    # display data
    print("nThe current items inside the list are: ")
    for x in range(0, numElems):
        print("Item #%d: %d" % ((x+1),arry[x]))

if __name__ == "__main__":
    main()
# http://programmingnotes.org/
			
				
					
				
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						def main():
    # declare variables   
    arry = [] # initialize the list
    numElems = 0
    
    # ask user how many items they want to place in list
    numElems = int(input("How many items do you want to place into the list?: "))
    
    # print a newline
    print("")
    
    # user enters data into list using a for loop
    # you can also use a while loop, but for loops are more common
    # when dealing with lists
    for x in range(0, numElems):
        arry.append(int(input("Enter item #%d: " % (x+1))))
    
    # display data
    print("nThe current items inside the list are: ")
    for x in range(0, numElems):
        print("Item #%d: %d" % ((x+1),arry[x]))
 
if __name__ == "__main__":
    main()
# http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

How many items do you want to place into the list?: 3
Enter item #1: 6 Enter item #2: 4 Enter item #3: 2008
The current items inside the list are: Item #1: 6 Item #2: 4 Item #3: 2008

Java || Snippet – How To Do Simple Math Using Integer Arrays

January 07, 2013 admin No comments

This page will consist of simple programs which demonstrate the process of doing simple math with numbers that are stored in an integer array.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Integer Arrays The "Random" Class For Loops Assignment Operators - Simple Math Operations Custom Setw/Setfill In Java

Note: In all of the examples on this page, a random number generator was used to place numbers into the array. If you do not know how to obtain data from the user, or if you do not know how to insert data into an array, click here for a demonstration.

===== ADDITION =====

The first code snippet will demonstrate how to add numbers together which are stored in an integer array. This example uses the “+=” assignment operator.





		
		
			#1 - Addition Using An Int Array
			
Java
			
			import java.util.Random;

public class Addition
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12; // const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 0;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe sum of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum + arry[x]
			totalSum += arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Random;
 
public class Addition
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12; // const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 0;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe sum of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum + arry[x]
			totalSum += arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

SAMPLE OUTPUT

Welcome to My Programming Notes' Java Program.
Original array values: 22 26 41 89 35 90 15 99 85 5 95 86 -------------------------------------------------- The sum of the items in the array is: 688

===== SUBTRACTION =====

The second code snippet will demonstrate how to subtract numbers which are stored in an integer array. This example uses the “-=” assignment operator.





		
		
			#2 - Subtraction Using An Int Array
			
Java
			
			import java.util.Random;

public class Subtraction
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 0;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe difference of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum - arry[x]
			totalSum -= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Random;
 
public class Subtraction
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 0;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe difference of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum - arry[x]
			totalSum -= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

SAMPLE OUTPUT

Welcome to My Programming Notes' Java Program.
Original array values: 99 92 91 26 1 52 98 62 51 22 64 65 -------------------------------------------------- The difference of the items in the array is: -723

===== MULTIPLICATION =====

The third code snippet will demonstrate how to multiply numbers which are stored in an integer array. This example uses the “*=” assignment operator.





		
		
			#3 - Multiplication Using An Int Array
			
Java
			
			import java.util.Random;

public class Multiplication
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 1;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe product of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum * arry[x]
			totalSum *= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Random;
 
public class Multiplication
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		int totalSum = 1;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe product of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum * arry[x]
			totalSum *= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

SAMPLE OUTPUT

Welcome to My Programming Notes' Java Program.
Original array values: 95 63 32 19 93 83 71 35 32 37 66 95 -------------------------------------------------- The product of the items in the array is: 494770176

===== DIVISION =====

The fourth code snippet will demonstrate how to divide numbers which are stored in an integer array. This example uses the “/=” assignment operator.





		
		
			#4 - Division Using An Int Array
			
Java
			
			import java.util.Random;

public class Division
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		double totalSum = 1;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe quotient of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum / arry[x]
			totalSum /= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Random;
 
public class Division
{
	// global variable declaration
	static Random rand = new Random();		
	static final int NUM_INTS = 12;	// const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[NUM_INTS]; // array is initialized using a const variable
		double totalSum = 1;		
		
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Display the original array values
		for(int x = 0; x < NUM_INTS; ++x)
		{
			System.out.print(arry[x]+"  ");
		}	
		
		// creates a line seperator if user wants to enter new data
		System.out.println("");
		setwRF("", 50, '-');
		
		System.out.print("nThe quotient of the items in the array is: ");
		// Find the sum of the values in the array
		for(int x = 0; x < NUM_INTS; ++x)
		{
			// the code below literally means
			// totalSum = totalSum / arry[x]
			totalSum /= arry[x];
		}
		// after the calculations are complete, display the total to the user
		System.out.println(totalSum);									
	}// end of main	
	
	public static void setwRF(String str, int width, char fill)
	{
		System.out.print(str);
		for (int x = str.length(); x < width; ++x)
		{
			System.out.print(fill);     
		}
	}// end of setwRF	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

SAMPLE OUTPUT

Welcome to My Programming Notes' Java Program.
Original array values: 28 85 90 52 1 64 93 85 4 22 4 28 -------------------------------------------------- The quotient of the items in the array is: 1.8005063061510687E-17

Java || Snippet – How To Find The Highest & Lowest Numbers Contained In An Integer Array

November 20, 2012 admin No comments

This page will consist of a simple demonstration for finding the highest and lowest numbers contained in an integer array.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Integer Arrays For Loops Custom Setw/Setfill In Java

Finding the highest/lowest values in an array can be found in one or two ways. The first way would be via a sort, which would obviously render the highest/lowest numbers contained in the array because the values would be sorted in order from highest to lowest. But a sort may not always be practical, especially when you want to keep the array values in the same order that they originally came in.

The second method of finding the highest/lowest values is by traversing through the array, literally checking each value it contains one by one to determine if the current number which is being compared truly is a target value or not. That method will be displayed below.





		
		
			Find The Highest/Lowest Numbers In An Array
			
Java
			
			import java.util.Random;

public class HighestLowestArray
{
	// global variable declaration
	final static int ARRAY_SIZE = 14; // const int allocating space for the array
	static Random rand = new Random(); // this is the call to the "Random" class
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[ARRAY_SIZE];
		int highestScore = -999999;
		int lowestScore = 999999;
	     
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < ARRAY_SIZE; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Output the original array values
		for(int x = 0; x < ARRAY_SIZE; ++x)
		{
			System.out.print(arry[x]+"  ");
		}
		System.out.println("");
		
		// creates a line seperator
		setwLF("",60,'-');
		
		// use a for loop to go thru the array checking to see the highest/lowest element
		System.out.print("nThese are the highest and lowest array values: ");
		for(int index=0; index < ARRAY_SIZE; ++index)
		{
			// if current score in the array is bigger than the current 'highestScore'
			// element, then set 'highestScore' equal to the current array element
			if(arry[index] > highestScore)
			{
				highestScore = arry[index];
			}
			// if current 'lowestScore' element is bigger than the current array element,
			//  then set 'lowestScore' equal to the current array element
			if(arry[index] < lowestScore)
			{
				lowestScore = arry[index];
			}
		}// end for loop
		
		// display the results to the user
		System.out.print("nHighest: "+highestScore);
		System.out.print("nLowest: "+lowestScore);
		System.out.println("");		
	}// end of main	
	
	static public void setwLF(String str, int width, char fill)
	{		
		for (int x = str.length(); x < width; ++x) 
		{
			System.out.print(fill);	
		}
		System.out.print(str);
	}// end of setwLF	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Random;
 
public class HighestLowestArray
{
	// global variable declaration
	final static int ARRAY_SIZE = 14; // const int allocating space for the array
	static Random rand = new Random(); // this is the call to the "Random" class
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int[] arry = new int[ARRAY_SIZE];
		int highestScore = -999999;
		int lowestScore = 999999;
	     
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// place random numbers into the array
		for(int x = 0; x < ARRAY_SIZE; ++x)
		{
			arry[x] = rand.nextInt(100)+1;
		} 
		
		System.out.println("Original array values:");
		// Output the original array values
		for(int x = 0; x < ARRAY_SIZE; ++x)
		{
			System.out.print(arry[x]+"  ");
		}
		System.out.println("");
		
		// creates a line seperator
		setwLF("",60,'-');
		
		// use a for loop to go thru the array checking to see the highest/lowest element
		System.out.print("nThese are the highest and lowest array values: ");
		for(int index=0; index < ARRAY_SIZE; ++index)
		{
			// if current score in the array is bigger than the current 'highestScore'
			// element, then set 'highestScore' equal to the current array element
			if(arry[index] > highestScore)
			{
				highestScore = arry[index];
			}
			// if current 'lowestScore' element is bigger than the current array element,
			//  then set 'lowestScore' equal to the current array element
			if(arry[index] < lowestScore)
			{
				lowestScore = arry[index];
			}
		}// end for loop
		
		// display the results to the user
		System.out.print("nHighest: "+highestScore);
		System.out.print("nLowest: "+lowestScore);
		System.out.println("");		
	}// end of main	
	
	static public void setwLF(String str, int width, char fill)
	{		
		for (int x = str.length(); x < width; ++x) 
		{
			System.out.print(fill);	
		}
		System.out.print(str);
	}// end of setwLF	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

Welcome to My Programming Notes' Java Program.
Original array values: 36 35 46 86 86 58 44 38 79 52 27 78 65 79 ------------------------------------------------------------ These are the highest and lowest array values: Highest: 86 Lowest: 27

Java || Snippet – How To Input Numbers Into An Integer Array & Display Its Contents Back To User

November 20, 2012 admin No comments

This snippet demonstrates how to place numbers into an integer array. It also shows how to display the contents of the array back to the user via stdout.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Integer Arrays For Loops Final Variables





		
		
			Insert & Display Items In An Array
			
Java
			
			import java.util.Scanner;

public class ArrayInput
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);	
	final static int ARRAY_SIZE = 100; // const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int numElems = 0;
		int[] myArray = new int[ARRAY_SIZE]; // declare array which has the ability to hold 100 elements
	     
		System.out.println("Welcome to My Programming Notes' Java Program.n");	
		
		// ask user how many items they want to place in array
		System.out.print("How many items do you want to place into the array?: ");
		numElems = cin.nextInt();
		
		System.out.println("");		
		// user enters data into array using a for loop
		// you can also use a while loop, but for loops are more common
		// when dealing with arrays
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("Enter item #"+(index+1)+": ");
			myArray[index] = cin.nextInt();
		} 
		
		// display data to user
		System.out.print("nThe current items inside the array are: ");
		
		// display contents inside array using a for loop
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("nItem #"+(index+1)+": "+myArray[index]);
		}
		System.out.println("");		
	}// end of main	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class ArrayInput
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);	
	final static int ARRAY_SIZE = 100; // const int allocating space for the array
	
	public static void main(String[] args)
	{
		// declare & initialize variables
		int numElems = 0;
		int[] myArray = new int[ARRAY_SIZE]; // declare array which has the ability to hold 100 elements
	     
		System.out.println("Welcome to My Programming Notes' Java Program.n");	
		
		// ask user how many items they want to place in array
		System.out.print("How many items do you want to place into the array?: ");
		numElems = cin.nextInt();
		
		System.out.println("");		
		// user enters data into array using a for loop
		// you can also use a while loop, but for loops are more common
		// when dealing with arrays
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("Enter item #"+(index+1)+": ");
			myArray[index] = cin.nextInt();
		} 
		
		// display data to user
		System.out.print("nThe current items inside the array are: ");
		
		// display contents inside array using a for loop
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("nItem #"+(index+1)+": "+myArray[index]);
		}
		System.out.println("");		
	}// end of main	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

Welcome to My Programming Notes' Java Program.
How many items do you want to place into the array?: 5 Enter item #1: 12 Enter item #2: 43 Enter item #3: 5 Enter item #4: 643 Enter item #5: 2321
The current items inside the array are: Item #1: 12 Item #2: 43 Item #3: 5 Item #4: 643 Item #5: 2321

C++ || Convert Numbers To Words Using A Switch Statement

July 21, 2012 admin No comments

This program demonstrates more practice using arrays and switch statements.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Integer Arrays Cin.get Isdigit For loops While Loops Switch Statements - How To Use

Using “cin.get(),” this program first asks the user to enter in a number (one at a time) that they wish to translate into words. If the text which was entered into the system is a number, the program will save the user input into an integer array. If the text is not a number, the input is discarded. After integer data is obtained, a for loop is used to traverse the integer array, passing the data to a switch statement, which translates the number to text.

This program is very simple, so it does not have the ability to display any number prefixes. As a result, if the number “1858” was entered into the system, the program would output the converted text: “One Eight Five Eight.”





		
		
			Convert Numbers To Words
			
C++
			
			#include <iostream>
#include <cctype>
using namespace std;
 
int main()
{
	// declare variables
	int numberArry[50];
	int numElems=0;
	char singleNum=' ';

	// ask the user for a number
	cout<<"Enter number: ";

	// get data from the user, one character at a time
	while(cin.get(singleNum) && singleNum != 'n')
	{
		// only numbers will be saved into the array, everything
		// else is ignored
		if(isdigit(singleNum))
		{
			// this converts a char into an integer using ascii values
			numberArry[numElems] = (singleNum)-'0'; 
			++numElems;
		}
	}

	cout<<endl;

	// using the data from the array, display the
	// numbers to the screen using a switch statement
	for(int index=0; index < numElems; ++index)
	{
		switch(numberArry[index])
		{
			case 0 :
				cout<<"Zero ";
				break;
			case 1 : 
				cout<<"One ";
				break;
			case 2: 
				cout<<"Two ";
				break;
			case 3: 
				cout<<"Three ";
				break;
			case 4:
				cout<<"Four ";
				break;
			case 5:
				cout<<"Five ";
				break;
			case 6:
				cout<<"Six ";
				break;
			case 7:
				cout<<"Seven ";
				break;
			case 8:
				cout<<"Eight ";
				break;
			case 9:
				cout<<"Nine ";
				break;
			default:
				cout<<"nERROR!n";
				break;
		}
	}
	cout<<endl;

	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <cctype>
using namespace std;
 
int main()
{
	// declare variables
	int numberArry[50];
	int numElems=0;
	char singleNum=' ';
 
	// ask the user for a number
	cout<<"Enter number: ";
 
	// get data from the user, one character at a time
	while(cin.get(singleNum) && singleNum != 'n')
	{
		// only numbers will be saved into the array, everything
		// else is ignored
		if(isdigit(singleNum))
		{
			// this converts a char into an integer using ascii values
			numberArry[numElems] = (singleNum)-'0'; 
			++numElems;
		}
	}
 
	cout<<endl;
 
	// using the data from the array, display the
	// numbers to the screen using a switch statement
	for(int index=0; index < numElems; ++index)
	{
		switch(numberArry[index])
		{
			case 0 :
				cout<<"Zero ";
				break;
			case 1 : 
				cout<<"One ";
				break;
			case 2: 
				cout<<"Two ";
				break;
			case 3: 
				cout<<"Three ";
				break;
			case 4:
				cout<<"Four ";
				break;
			case 5:
				cout<<"Five ";
				break;
			case 6:
				cout<<"Six ";
				break;
			case 7:
				cout<<"Seven ";
				break;
			case 8:
				cout<<"Eight ";
				break;
			case 9:
				cout<<"Nine ";
				break;
			default:
				cout<<"nERROR!n";
				break;
		}
	}
	cout<<endl;
 
	return 0;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output
Note: The code was compiled four separate times to display different output

======= Run #1 =======
Enter number: 77331 Seven Seven Three Three One ======= Run #2 ======= Enter number: 234-43-1275 Two Three Four Four Three One Two Seven Five ======= Run #3 ======= Enter number: 1(800) 123-5678 One Eight Zero Zero One Two Three Five Six Seven Eight ======= Run #4 ======= Enter number: This 34 Is 24 A 5 Number 28
Three Four Two Four Five Two Eight

C++ || Char Array – Palindrome Number Checker Using A Character Array, Strlen, Strcpy, & Strcmp

July 10, 2012 admin No comments

The following is a palindromic number checking program, which demonstrates more use of character array’s, Strlen, & Strcmp.

Want sample code for a palindrome checker which works for numbers and words? Click here.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Character Arrays How to reverse a character array Palindrome - What is it? Strlen Strcpy Strcmp Isdigit Atoi - Convert a char array to a number Do/While Loops For Loops

This program first asks the user to enter a number that they wish to compare for similarity. If the number which was entered into the system is a palindrome, the program will prompt a message to the user via cout. This program determines similarity by using the strcmp function to compare two arrays together. Using a for loop, this program also demonstrates how to reverse a character array, aswell as demonstrates how to determine if the text contained in a character array is a number or not.

This program will repeatedly prompt the user for input until an “exit code” is obtained. The designated exit code in this program is the number 0 (zero). So the program will not stop asking for user input until the number 0 is entered into the program.





		
		
			Palindrome Number Checker Using A Char Array
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jul 10, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Palindrome number checker
// ============================================================================
#include <iostream>
#include <cctype>
#include <cstring>
#include <cstdlib>
using namespace std;

// function prototypes
void Reverse(char arry[]);
bool IsArryANum(char arry[]);

// constant, which is the exit value 
const char* EXIT_VALUE = "0";

int main()
{
    // declare variables
    char arry[80];
    char arryReversed[80];
    
    do{// get data from user using do/while loop
        cout<<"\nEnter a positive integer, or ("<<EXIT_VALUE<<") to exit: ";
        
        cin >> arry;
        
        if(atoi(arry) < 0) // check for negative numbers
        {
            cout <<"\n*** Error: "<<arry<<" must be greater than zero\n";
        }
        else if(!IsArryANum(arry)) // check for any letters 
        {
            cout <<"\n*** Error: "<<arry<<" is not an integer\n";
        }
        else if(strcmp(EXIT_VALUE, arry) == 0) // check for "exit code"
        {
            cout <<"\nExiting program...\n";
        }
        else // if all else is good, determine if number is a palindrome 
        {
            // copy the user input from the first array (arry)
            // into the second array (arryReversed)
            strcpy(arryReversed, arry);

            // function call to reverse the contents inside the
            // "arryReversed" array to check for similarity
            Reverse(arryReversed);
            
            cout <<endl<<arry;

            // use strcmp to determine if the two arrays are the same
            if(strcmp(arryReversed, arry) == 0)
            {
                cout <<" is a Palindrome..\n";
            }
            else
            {
                cout <<" is NOT a Palindrome!\n";
            }
        }
    }while(strcmp(EXIT_VALUE, arry) != 0); // keep going until user enters the exit value

    cout <<"\nBYE!\n";
    
    return 0;
}// end of main

void Reverse(char arry[])
{
    // get the length of the current word in the array index
    int length = strlen(arry)-1;
    
    // increment thru each letter within the current char array index
    // reversing the order of the array
    for (int currentChar=0; currentChar < length; --length, ++currentChar)
    {
        // copy 1st letter in the array index into temp
        char temp = arry[currentChar];
        // copy last letter in the array index into the 1st array index
        arry[currentChar] = arry[length];
        // copy temp into last array index
        arry[length] = temp;
    }
}// end of Reverse

bool IsArryANum(char arry[])
{
    // LOOP UNTIL U REACH THE NULL CHARACTER,
    // AKA THE END OF THE CHAR ARRAY
    for(int x=0; arry[x]!='\0'; ++x)
    {               
        // if the current char isnt a number,
        // exit the loop & return false
        if(!isdigit(arry[x])) 
        {
            return false;
        }
    }
    return true;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jul 10, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Palindrome number checker
// ============================================================================
#include <iostream>
#include <cctype>
#include <cstring>
#include <cstdlib>
using namespace std;
 
// function prototypes
void Reverse(char arry[]);
bool IsArryANum(char arry[]);
 
// constant, which is the exit value 
const char* EXIT_VALUE = "0";
 
int main()
{
    // declare variables
    char arry[80];
    char arryReversed[80];
    
    do{// get data from user using do/while loop
        cout<<"\nEnter a positive integer, or ("<<EXIT_VALUE<<") to exit: ";
        
        cin >> arry;
        
        if(atoi(arry) < 0) // check for negative numbers
        {
            cout <<"\n*** Error: "<<arry<<" must be greater than zero\n";
        }
        else if(!IsArryANum(arry)) // check for any letters 
        {
            cout <<"\n*** Error: "<<arry<<" is not an integer\n";
        }
        else if(strcmp(EXIT_VALUE, arry) == 0) // check for "exit code"
        {
            cout <<"\nExiting program...\n";
        }
        else // if all else is good, determine if number is a palindrome 
        {
            // copy the user input from the first array (arry)
            // into the second array (arryReversed)
            strcpy(arryReversed, arry);
 
            // function call to reverse the contents inside the
            // "arryReversed" array to check for similarity
            Reverse(arryReversed);
            
            cout <<endl<<arry;
 
            // use strcmp to determine if the two arrays are the same
            if(strcmp(arryReversed, arry) == 0)
            {
                cout <<" is a Palindrome..\n";
            }
            else
            {
                cout <<" is NOT a Palindrome!\n";
            }
        }
    }while(strcmp(EXIT_VALUE, arry) != 0); // keep going until user enters the exit value
 
    cout <<"\nBYE!\n";
    
    return 0;
}// end of main
 
void Reverse(char arry[])
{
    // get the length of the current word in the array index
    int length = strlen(arry)-1;
    
    // increment thru each letter within the current char array index
    // reversing the order of the array
    for (int currentChar=0; currentChar < length; --length, ++currentChar)
    {
        // copy 1st letter in the array index into temp
        char temp = arry[currentChar];
        // copy last letter in the array index into the 1st array index
        arry[currentChar] = arry[length];
        // copy temp into last array index
        arry[length] = temp;
    }
}// end of Reverse
 
bool IsArryANum(char arry[])
{
    // LOOP UNTIL U REACH THE NULL CHARACTER,
    // AKA THE END OF THE CHAR ARRAY
    for(int x=0; arry[x]!='\0'; ++x)
    {               
        // if the current char isnt a number,
        // exit the loop & return false
        if(!isdigit(arry[x])) 
        {
            return false;
        }
    }
    return true;
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output

Enter a positive integer, or (0) to exit: L33T
*** error: "L33T" is not an integer Enter a positive integer, or (0) to exit: -728 *** error: -728 must be greater than zero Enter a positive integer, or (0) to exit: 1858 1858 is NOT a Palindrome! Enter a positive integer, or (0) to exit: 7337 7337 is a Palindrome.. Enter a positive integer, or (0) to exit: 0 Exiting program...
BYE!

Java || Searching An Integer Array For A Target Value

July 06, 2012 admin No comments

Here is another actual homework assignment which was presented in an intro to programming class which was used to introduce more practice using integer arrays.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Integer Arrays For Loops Methods (A.K.A "Functions") - What Are They? Final Variables If/Else Statements

This is a small and simple program which demonstrates how to search for a target value which is stored in an integer array. This program first prompts the user to enter five values into an int array. After the user enters all the values into the system, it then displays a prompt asking the user for a search value. Once it has a search value, the program searches through the array looking for the target value; and wherever the value is found, the program display’s the current array index in which that target value is located. After it displays all the locations where the target value resides, it display’s the total number of occurrences the search value was found within the array.





		
		
			Array Search
			
Java
			
			import java.util.Scanner;

public class ArraySearch
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	static final int NUM_INTS = 5;
	
	public static void main(String[] args)
	{
		// declare variables 
		int searchValue = 0;
		int numOccurences = 0;
		int[] numValues = new int[NUM_INTS]; // int array size is initialized with a const value
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");		
		
		// get data from user via a 'for loop'
		System.out.println("Please enter "+ NUM_INTS +" integer values:");
		
		for (int index=0; index < NUM_INTS; ++index)
		{
			System.out.print("#" + (index + 1) + ": ");
			numValues[index] = cin.nextInt();
		}
		
		// get a search value from the user
		System.out.print("Please enter a search value: ");
		searchValue = cin.nextInt();
		System.out.println("");		
		
		// finds the number of occurences the search value was found in the array
		numOccurences = SearchArray(numValues, searchValue);
		
		// display data to user
		System.out.println("nThe total occurrences of value "+ searchValue 
			+ " within the array is: " + numOccurences);		
	}// end of main
	
	// ==== SearchArray ===========================================================
	//
	// This method will take as input the array, the number of array 
	// elements, and the target value to search for. The function will traverse 
	// the array looking for the target value, and when it finds it, display the 
	// index location within the array.
	// 
	// Input:
	//	      limit [IN]  -- the array, the number of array 
	//				elements, and the target value
	//
	// Output:
	//	      The total number of occurrences of the target value in the array
	//
	// ============================================================================
	public static int SearchArray(int[] numValues, int searchValue)
	{
		int numFound=0;
		for (int index=0; index < NUM_INTS; ++index)
		{
			if (numValues[index] == searchValue)
			{
				System.out.println("t" + searchValue + " was found at array " +
						"index #" + index);
				++numFound; // if the search values was found,
				           // increment the variable by 1
			}
		}
		return numFound;
	}
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class ArraySearch
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	static final int NUM_INTS = 5;
	
	public static void main(String[] args)
	{
		// declare variables 
		int searchValue = 0;
		int numOccurences = 0;
		int[] numValues = new int[NUM_INTS]; // int array size is initialized with a const value
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");		
		
		// get data from user via a 'for loop'
		System.out.println("Please enter "+ NUM_INTS +" integer values:");
		
		for (int index=0; index < NUM_INTS; ++index)
		{
			System.out.print("#" + (index + 1) + ": ");
			numValues[index] = cin.nextInt();
		}
		
		// get a search value from the user
		System.out.print("Please enter a search value: ");
		searchValue = cin.nextInt();
		System.out.println("");		
		
		// finds the number of occurences the search value was found in the array
		numOccurences = SearchArray(numValues, searchValue);
		
		// display data to user
		System.out.println("nThe total occurrences of value "+ searchValue 
			+ " within the array is: " + numOccurences);		
	}// end of main
	
	// ==== SearchArray ===========================================================
	//
	// This method will take as input the array, the number of array 
	// elements, and the target value to search for. The function will traverse 
	// the array looking for the target value, and when it finds it, display the 
	// index location within the array.
	// 
	// Input:
	//	      limit [IN]  -- the array, the number of array 
	//				elements, and the target value
	//
	// Output:
	//	      The total number of occurrences of the target value in the array
	//
	// ============================================================================
	public static int SearchArray(int[] numValues, int searchValue)
	{
		int numFound=0;
		for (int index=0; index < NUM_INTS; ++index)
		{
			if (numValues[index] == searchValue)
			{
				System.out.println("t" + searchValue + " was found at array " +
						"index #" + index);
				++numFound; // if the search values was found,
				           // increment the variable by 1
			}
		}
		return numFound;
	}
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output:
Note: The code was compiled 3 separate times to display the different outputs its able to produce

====== RUN 1 ======
Welcome to My Programming Notes' Java Program. Please enter 5 integer values: #1: 25 #2: 25 #3: 25 #4: 25 #5: 25 Please enter a search value: 25 25 was found at array index #0 25 was found at array index #1 25 was found at array index #2 25 was found at array index #3 25 was found at array index #4 The total occurrences of value 25 within the array is: 5 ====== RUN 2 ====== Welcome to My Programming Notes' Java Program. Please enter 5 integer values: #1: 8 #2: 19 #3: 97 #4: 56 #5: 8 Please enter a search value: 8 8 was found at array index #0 8 was found at array index #4 The total occurrences of value 8 within the array is: 2 ====== RUN 3 ====== Welcome to My Programming Notes' Java Program. Please enter 5 integer values: #1: 78 #2: 65 #3: 3 #4: 45 #5: 89 Please enter a search value: 12
The total occurrences of value 12 within the array is: 0

Java || Find The Prime, Perfect & All Known Divisors Of A Number Using A For, While & Do/While Loop

June 24, 2012 admin No comments

This program was designed to better understand how to use different loops which are available in Java, as well as more practice using objects with classes.

This program first asks the user to enter a non negative number. After it obtains a non negative integer from the user, the program determines if the user obtained number is a prime number or not, aswell as determining if the user obtained number is a perfect number or not. After it obtains its results, the program will display to the screen if the user inputted number is prime/perfect number or not. The program will also display a list of all the possible divisors of the user obtained number via stdout.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Class Objects - How TO Use Constructors - What Are They? Do/While Loop While Loop For Loop Modulus Basic Math - Prime Numbers Basic Math - Perfect Numbers Basic Math - Divisors





		
		
			Is It Prime or Perfect? List All Possible Divisors
			
Java
			
			import java.util.Scanner;

public class PrimePerfectNums
{
	// global variable declaration
	int userInput = 0;	
	static Scanner cin = new Scanner(System.in);
	
	public PrimePerfectNums(int input)
	{// this is the constructor
		// give the global variable a value
		userInput = input;

	}// end of PrimePerfectNums
	
	public void CalcPrimePerfect() 
	{
		// declare variables
		int divisor = 0;
		int sumOfDivisors = 0;		
		
		System.out.print("nInput number: " + userInput);
		
		// for loop adds sum of all possible divisors
		for(int counter=1; counter <= userInput; ++counter)
		{
			divisor = (userInput % counter);
			if(divisor == 0)
			{
				// this will repeatedly add the found divisors together
				sumOfDivisors += counter;
			}
		}
		
		System.out.println("");
		// uses the 'sumOfDivisors' variable from ^ above for loop to
		// check if 'userInput' is prime
		if(userInput == (sumOfDivisors - 1))
		{
			System.out.print(userInput + " is a prime number.");
		}
		else
		{
			System.out.print(userInput + " is not a prime number.");
		}
		
		System.out.println("");
		// uses the 'sumOfDivisors' variable from ^ above for loop to
		// check if 'userInput' is a perfect number
		if (userInput == (sumOfDivisors - userInput))
		{
			System.out.print(userInput + " is a perfect number.");
		}
		else
		{
			System.out.print(userInput + " is not a perfect number.");
		}
		
		System.out.print("nDivisors of " + userInput + " are: ");
		// for loop lists all the possible divisors for the
		// 'userInput' variable by using the modulus operator
		for(int counter=1; counter <= userInput; ++counter)
		{
			divisor = (userInput % counter);
			if(divisor == 0 && counter !=userInput)
			{
				System.out.print(counter + ", ");
			}
		}
		
		System.out.print("and " + userInput);					
	}// end of CalcPrimePerfect
	
	public static void main(String[] args)
	{
		// declare variables
		int input = 0;
		char response ='n';
		
		do{ // this is the start of the do/while loop
			
			System.out.print("Enter a number: ");
			input = cin.nextInt();
			
			// if the user inputs a negative number, do this code
			while(input < 0) 
			{
				System.out.print("ntSorry, but the number entered is less " +
						"than the allowable limit.ntPlease try again.....");
				System.out.print("nnEnter an number: ");
				input = cin.nextInt();
			}
			// entry point to class declaration
			PrimePerfectNums myClass = new PrimePerfectNums(input);
			
			// function call to obtain data using the number
			// which was passed from main to the constructor
			myClass.CalcPrimePerfect();
			
			// asks user if they want to enter new data
			System.out.print("nntDo you want to input another number?(Y/N): ");
			response = cin.next().toLowerCase().charAt(0);
			
			System.out.println("---------------------------" +
				"---------------------------------");		
		}while(response =='y');
		// ^ End of the do/while loop. As long as the user chooses
		// 'Y' the loop will keep going.
		// It stops when the user chooses the letter 'N'
		
		System.out.println("BYE!");		
	}// end of main	
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class PrimePerfectNums
{
	// global variable declaration
	int userInput = 0;	
	static Scanner cin = new Scanner(System.in);
	
	public PrimePerfectNums(int input)
	{// this is the constructor
		// give the global variable a value
		userInput = input;
 
	}// end of PrimePerfectNums
	
	public void CalcPrimePerfect() 
	{
		// declare variables
		int divisor = 0;
		int sumOfDivisors = 0;		
		
		System.out.print("nInput number: " + userInput);
		
		// for loop adds sum of all possible divisors
		for(int counter=1; counter <= userInput; ++counter)
		{
			divisor = (userInput % counter);
			if(divisor == 0)
			{
				// this will repeatedly add the found divisors together
				sumOfDivisors += counter;
			}
		}
		
		System.out.println("");
		// uses the 'sumOfDivisors' variable from ^ above for loop to
		// check if 'userInput' is prime
		if(userInput == (sumOfDivisors - 1))
		{
			System.out.print(userInput + " is a prime number.");
		}
		else
		{
			System.out.print(userInput + " is not a prime number.");
		}
		
		System.out.println("");
		// uses the 'sumOfDivisors' variable from ^ above for loop to
		// check if 'userInput' is a perfect number
		if (userInput == (sumOfDivisors - userInput))
		{
			System.out.print(userInput + " is a perfect number.");
		}
		else
		{
			System.out.print(userInput + " is not a perfect number.");
		}
		
		System.out.print("nDivisors of " + userInput + " are: ");
		// for loop lists all the possible divisors for the
		// 'userInput' variable by using the modulus operator
		for(int counter=1; counter <= userInput; ++counter)
		{
			divisor = (userInput % counter);
			if(divisor == 0 && counter !=userInput)
			{
				System.out.print(counter + ", ");
			}
		}
		
		System.out.print("and " + userInput);					
	}// end of CalcPrimePerfect
	
	public static void main(String[] args)
	{
		// declare variables
		int input = 0;
		char response ='n';
		
		do{ // this is the start of the do/while loop
			
			System.out.print("Enter a number: ");
			input = cin.nextInt();
			
			// if the user inputs a negative number, do this code
			while(input < 0) 
			{
				System.out.print("ntSorry, but the number entered is less " +
						"than the allowable limit.ntPlease try again.....");
				System.out.print("nnEnter an number: ");
				input = cin.nextInt();
			}
			// entry point to class declaration
			PrimePerfectNums myClass = new PrimePerfectNums(input);
			
			// function call to obtain data using the number
			// which was passed from main to the constructor
			myClass.CalcPrimePerfect();
			
			// asks user if they want to enter new data
			System.out.print("nntDo you want to input another number?(Y/N): ");
			response = cin.next().toLowerCase().charAt(0);
			
			System.out.println("---------------------------" +
				"---------------------------------");		
		}while(response =='y');
		// ^ End of the do/while loop. As long as the user chooses
		// 'Y' the loop will keep going.
		// It stops when the user chooses the letter 'N'
		
		System.out.println("BYE!");		
	}// end of main	
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

Once compiled, you should get this as your output:

Enter a number: 41
Input number: 41 41 is a prime number. 41 is not a perfect number. Divisors of 41 are: 1, and 41 Do you want to input another number?(Y/N): y ------------------------------------------------------------ Enter a number: 496 Input number: 496 496 is not a prime number. 496 is a perfect number. Divisors of 496 are: 1, 2, 4, 8, 16, 31, 62, 124, 248, and 496 Do you want to input another number?(Y/N): y ------------------------------------------------------------ Enter a number: 1858 Input number: 1858 1858 is not a prime number. 1858 is not a perfect number. Divisors of 1858 are: 1, 2, 929, and 1858 Do you want to input another number?(Y/N): y ------------------------------------------------------------ Enter a number: -9 Sorry, but the number entered is less than the allowable limit. Please try again..... Enter an number: 12 Input number: 12 12 is not a prime number. 12 is not a perfect number. Divisors of 12 are: 1, 2, 3, 4, 6, and 12
Do you want to input another number?(Y/N): n ------------------------------------------------------------ BYE!

Java || Find The Average Using an Array – Omit Highest And Lowest Scores

June 22, 2012 admin No comments

This page will consist of two programs which calculates the average of a specific amount of numbers using an array.

REQUIRED KNOWLEDGE FOR BOTH PROGRAMS

Double Data Type Final Variables Arrays For Loops Assignment Operators Basic Math - How To Find The Average

====== FIND THE AVERAGE USING AN ARRAY ======

The first program is fairly simple, and it was used to introduce the array concept. The program prompts the user to enter the total amount of numbers they want to find the average for, then the program displays the answer to them via stdout.





		
		
			#1 - Find The Average
			
Java
			
			import java.util.Scanner;

public class FindTheAverage
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	
	public static void main(String[] args)
	{
		// declare variables 		
		int numElems = 0;
		double sum = 0;
		double[] average = new double[100]; // declare array which has the ability to hold 100 elements
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// determine how many numbers the user wants in the array
		System.out.print("How many numbers do you want to find the average for?: ");
		numElems = cin.nextInt();
		
		System.out.println("");
		
		// user enters data into array using a for loop
		// you can also use a while loop, but for loops are more common
		// when dealing with arrays
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("Enter value #" +(index+1)+ ": ");
			average[index] = cin.nextDouble();
			sum += average[index];
		}
		
		// find the average. 
		// Note: the expression below literally 
		// means: sum = sum / numElems;
		sum /= numElems;
		
		System.out.println("nThe average of the " + numElems + " numbers is " + sum);
	}// end of main
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class FindTheAverage
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	
	public static void main(String[] args)
	{
		// declare variables 		
		int numElems = 0;
		double sum = 0;
		double[] average = new double[100]; // declare array which has the ability to hold 100 elements
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		// determine how many numbers the user wants in the array
		System.out.print("How many numbers do you want to find the average for?: ");
		numElems = cin.nextInt();
		
		System.out.println("");
		
		// user enters data into array using a for loop
		// you can also use a while loop, but for loops are more common
		// when dealing with arrays
		for(int index=0; index < numElems; ++index)
		{
			System.out.print("Enter value #" +(index+1)+ ": ");
			average[index] = cin.nextDouble();
			sum += average[index];
		}
		
		// find the average. 
		// Note: the expression below literally 
		// means: sum = sum / numElems;
		sum /= numElems;
		
		System.out.println("nThe average of the " + numElems + " numbers is " + sum);
	}// end of main
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

ARRAY
Notice the array declaration on line #13. The type of array being used in this program is a dynamic array, which has the ability to store up to 100 integer elements in the array. You can change the number of elements its able to store to a higher or lower number if you wish.

FOR LOOP
Lines 27-32 contains a for loop, which is used to actually store the data inside of the array. Without some type of loop, it is virtually impossible for the user to input data into the array; that is, unless you want to add 100 different println statements into your code asking the user to input data. Line 31 uses the assignment operator “+=” which gives us a running total of the data that is being inputted into the array. Note the loop only stores as many elements as the user so desires, so if the user only wants to input 3 numbers into the array, the for loop will only execute 3 times.

Once compiled, you should get this as your output:

Welcome to My Programming Notes' Java Program.
How many numbers do you want to find the average for?: 4 Enter value #1: 21 Enter value #2: 24 Enter value #3: 19 Enter value #4: 17 The average of the 4 numbers is 20.25

====== FIND THE AVERAGE – OMIT HIGHEST AND LOWEST SCORES ======

The second program is really practical in a real world setting. We were asked to create a program for a fictional competition which had 6 judges. The 6 judges each gave a score of the performance for a competitor in a competition, (i.e a score of 1-10), and we were asked to find the average of those scores, omitting the highest/lowest results. The program was to store the scores into an array, display the scores back to the user via stdout, display the highest and lowest scores among the 6 obtained, display the average of the 6 scores, and finally display the average adjusted scores omitting the highest and lowest result.





		
		
			#2 - Find The Average Omitting The Highest/Lowest Score
			
Java
			
			import java.util.Scanner;

public class FindOmittedAverage
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	static final int NUM_JUDGES = 6;
	
	public static void main(String[] args)
	{
		// declare variables
		double highestScore = -999999;
		double lowestScore = 999999;
		double sumOfScores = 0;
		double avgScores = 0;
		double[] scores = new double[NUM_JUDGES]; // array is initialized using a final variable
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		System.out.print("Judges, enter one score each for the current competitor: ");
		
		// use a for loop to obtain data from  user using the final variable
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			// this puts data into the current array index
			scores[index] = cin.nextDouble();
			
			// this calculates a running total of all the scores
			// adding each element in the array together
			sumOfScores += scores[index];
			
			// if current score in the array index is bigger than the current 'highestScore'
			// value, then set 'highestScore' equal to the current value in the array
			if(scores[index] > highestScore)
			{
				highestScore = scores[index];
			}
			
			// if current score in the array index is smaller than the current 'lowestScore'
			// value, then set 'lowestScore' equal to the current value in the array
			if(lowestScore > scores[index])
			{
				lowestScore = scores[index];
			}			
		}
		
		System.out.print("nThese are the scores from the " + NUM_JUDGES + " judges: ");
		
		// use another for loop to redisplay the data back to the user via stdout
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			System.out.print("nThe score for judge #"+(index+1)+" is: "+scores[index]);
		} 
		
		// display the highest/lowest numbers to the screen
		System.out.print("nnThese are the highest and lowest scores: ");
		System.out.print("ntHighest: "+ highestScore);
		System.out.print("ntLowest: "+ lowestScore);
		
		// find the average
		avgScores = sumOfScores/NUM_JUDGES;
		System.out.print("nThe average score is: "+ avgScores);
		
		// reset data back to 0 so we can find the ommitted average
		sumOfScores = 0;
		avgScores = 0;
		
		System.out.print("nThe average adjusted score omitting the highest and lowest result is: ");
		
		// final loop, which calculates a running total, adding each element
		// in the array together, this time omitting the highest/lowest scores
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			// IF(current score isnt equal to the highest elem) AND (current score isnt equal lowest elem)
			// THEN create a running total
			if((scores[index] != highestScore) && (scores[index] != lowestScore))
			{
				sumOfScores += scores[index];
			}
		}	
		
		// find the average, minus the 2 scores
		avgScores = sumOfScores/(NUM_JUDGES-2);
		
		System.out.print(avgScores);
	}// end of main
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class FindOmittedAverage
{
	// global variable declaration
	static Scanner cin = new Scanner(System.in);
	static final int NUM_JUDGES = 6;
	
	public static void main(String[] args)
	{
		// declare variables
		double highestScore = -999999;
		double lowestScore = 999999;
		double sumOfScores = 0;
		double avgScores = 0;
		double[] scores = new double[NUM_JUDGES]; // array is initialized using a final variable
		
		// display message to screen
		System.out.println("Welcome to My Programming Notes' Java Program.n");
		
		System.out.print("Judges, enter one score each for the current competitor: ");
		
		// use a for loop to obtain data from  user using the final variable
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			// this puts data into the current array index
			scores[index] = cin.nextDouble();
			
			// this calculates a running total of all the scores
			// adding each element in the array together
			sumOfScores += scores[index];
			
			// if current score in the array index is bigger than the current 'highestScore'
			// value, then set 'highestScore' equal to the current value in the array
			if(scores[index] > highestScore)
			{
				highestScore = scores[index];
			}
			
			// if current score in the array index is smaller than the current 'lowestScore'
			// value, then set 'lowestScore' equal to the current value in the array
			if(lowestScore > scores[index])
			{
				lowestScore = scores[index];
			}			
		}
		
		System.out.print("nThese are the scores from the " + NUM_JUDGES + " judges: ");
		
		// use another for loop to redisplay the data back to the user via stdout
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			System.out.print("nThe score for judge #"+(index+1)+" is: "+scores[index]);
		} 
		
		// display the highest/lowest numbers to the screen
		System.out.print("nnThese are the highest and lowest scores: ");
		System.out.print("ntHighest: "+ highestScore);
		System.out.print("ntLowest: "+ lowestScore);
		
		// find the average
		avgScores = sumOfScores/NUM_JUDGES;
		System.out.print("nThe average score is: "+ avgScores);
		
		// reset data back to 0 so we can find the ommitted average
		sumOfScores = 0;
		avgScores = 0;
		
		System.out.print("nThe average adjusted score omitting the highest and lowest result is: ");
		
		// final loop, which calculates a running total, adding each element
		// in the array together, this time omitting the highest/lowest scores
		for(int index=0; index < NUM_JUDGES; ++index)
		{
			// IF(current score isnt equal to the highest elem) AND (current score isnt equal lowest elem)
			// THEN create a running total
			if((scores[index] != highestScore) && (scores[index] != lowestScore))
			{
				sumOfScores += scores[index];
			}
		}	
		
		// find the average, minus the 2 scores
		avgScores = sumOfScores/(NUM_JUDGES-2);
		
		System.out.print(avgScores);
	}// end of main
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

FINAL
A final variable was declared and used to initialize the array (line 7). This was used to initialize the size of the array.

FOR LOOPS
Once again loops were used to traverse the array, as noted on lines 24, 51 and 73. The final variable was also used within the for loops, making it easier to modify the code if its necessary to reduce or increase the number of available judges.

HIGHEST/LOWEST SCORES
This is noted on lines 35-45, and it is really simple to understand the process once you see the code.

OMITTING HIGHEST/LOWEST SCORE
Lines 73-81 highlights this process. The loop basically traverses the array, skipping over the highest/lowest elements.

Once compiled, you should get this as your output

Welcome to My Programming Notes' Java Program.
Judges, enter one score each for the current competitor: 123 453 -789 2 23345 987 These are the scores from the 6 judges: The score for judge #1 is: 123.0 The score for judge #2 is: 453.0 The score for judge #3 is: -789.0 The score for judge #4 is: 2.0 The score for judge #5 is: 23345.0 The score for judge #6 is: 987.0
These are the highest and lowest scores: Highest: 23345.0 Lowest: -789.0 The average score is: 4020.1666666666665 The average adjusted score omitting the highest and lowest result is: 391.25

Java || Snippet – Custom Setw & Setfill Sample Code For Java

June 06, 2012 admin No comments

This page will consist of a brief implementation of setw/ios::width and setfill/ios::fill in Java.

If you are a C++ programmer, no doubt you have used the setw and setfill commands many times. It makes formatting output like this very clean and simple (see below).

Ending balance:................. $ 6433.47 Amount of deposits:............. $ 1750.00 Amount of withdrawals:.......... $ 420.00 Amount of interest earned:...... $ 103.47

But to my amazement, I could not find a very suitable replacement for the setw/setfill functions in Java. Using simple for loops, the methods provided on this page has the ability to mimic both functions which are available in C++.

Included in the sample code are the following:

== SETW ==
(1) right - Justifies string data of size "width," filling the width to the start of the string with whitespace (2) left - Justifies string data of size "width," filling the width to the end of the string with whitespace == SETFILL == (3) right - Justifies string data of size "width," filling the width to the start of the string with a filler character
(4) left - Justifies string data of size "width," filling the width to the end of the string with a filler character





		
		
			Setw & Setfill For Java
			
Java
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jun 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  Setw.java
//    Description: Demonstrate the use of custom setw/ios::width and
//      setfill/ios::fill functions for text formatting in Java.
// ============================================================================
public class Setw
{
    // ==== right ======================================================================
    //
    // - Set field width right align -
    //
    // Justifies string data of size "width," filling the width to the start of
    // the string with whitespace (' ').
    //
    // - USAGE -
    // right(<String> the text you wish to format, <int> size of width to be formated);
    //
    // =================================================================================
    public static void right(String str, int width)
    {
        right(str, width, ' ');
    }// end of right

    // ==== left ======================================================================
    //
    // - Set field width left align -
    //
    // Justifies string data of size "width," filling the width to the end of
    // the string with whitespace (' ').
    //
    // - USAGE -
    // left(<String> the text you wish to format, <int> size of width to be formated);
    //
    // =================================================================================
    public static void left(String str, int width)
    {
        left(str, width, ' ');
    }// end of left

    // ==== right ======================================================================
    //
    // - Set field width right align fill -
    //
    // Justifies string data of size "width," filling the width to the start of
    // the string with a filler character.
    //
    // Use this method (instead of using 'left/right') when you want so specify the
    // type of filler you want to use
    //
    // - USAGE -
    // right(<String> the text you wish to format,
    // <int> size of width to be formated, <char> the type of filler to be displayed);
    //
    // =================================================================================
    public static void right(String str, int width, char fill)
    {
        for (int x = str.length(); x < width; ++x)
        {
            System.out.print(fill);
        }
        System.out.print(str);
    }// end of right

    // ==== left ======================================================================
    //
    // - Set field width left align fill -
    //
    // Justifies string data of size "width," filling the width to the end of
    // the string with a filler character.
    //
    // Use this method (instead of using 'left/right') when you want so specify the
    // type of filler you want to use
    //
    // - USAGE -
    // left(<String> the text you wish to format,
    // <int> size of width to be formated, <char> the type of filler to be displayed);
    //
    // =================================================================================
    public static void left(String str, int width, char fill)
    {
        System.out.print(str);
        for (int x = str.length(); x < width; ++x)
        {
            System.out.print(fill);
        }
    }// end of left
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jun 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  Setw.java
//    Description: Demonstrate the use of custom setw/ios::width and
//      setfill/ios::fill functions for text formatting in Java.
// ============================================================================
public class Setw
{
    // ==== right ======================================================================
    //
    // - Set field width right align -
    //
    // Justifies string data of size "width," filling the width to the start of
    // the string with whitespace (' ').
    //
    // - USAGE -
    // right(<String> the text you wish to format, <int> size of width to be formated);
    //
    // =================================================================================
    public static void right(String str, int width)
    {
        right(str, width, ' ');
    }// end of right
 
    // ==== left ======================================================================
    //
    // - Set field width left align -
    //
    // Justifies string data of size "width," filling the width to the end of
    // the string with whitespace (' ').
    //
    // - USAGE -
    // left(<String> the text you wish to format, <int> size of width to be formated);
    //
    // =================================================================================
    public static void left(String str, int width)
    {
        left(str, width, ' ');
    }// end of left
 
    // ==== right ======================================================================
    //
    // - Set field width right align fill -
    //
    // Justifies string data of size "width," filling the width to the start of
    // the string with a filler character.
    //
    // Use this method (instead of using 'left/right') when you want so specify the
    // type of filler you want to use
    //
    // - USAGE -
    // right(<String> the text you wish to format,
    // <int> size of width to be formated, <char> the type of filler to be displayed);
    //
    // =================================================================================
    public static void right(String str, int width, char fill)
    {
        for (int x = str.length(); x < width; ++x)
        {
            System.out.print(fill);
        }
        System.out.print(str);
    }// end of right
 
    // ==== left ======================================================================
    //
    // - Set field width left align fill -
    //
    // Justifies string data of size "width," filling the width to the end of
    // the string with a filler character.
    //
    // Use this method (instead of using 'left/right') when you want so specify the
    // type of filler you want to use
    //
    // - USAGE -
    // left(<String> the text you wish to format,
    // <int> size of width to be formated, <char> the type of filler to be displayed);
    //
    // =================================================================================
    public static void left(String str, int width, char fill)
    {
        System.out.print(str);
        for (int x = str.length(); x < width; ++x)
        {
            System.out.print(fill);
        }
    }// end of left
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted lines are sections of interest to look out for.

Also, you must understand minimal object oriented programming to use this code!

The code is heavily commented, so no further insight is necessary. If you have any questions, feel free to leave a comment below.

===== DEMONSTRATION HOW TO USE =====

Use of the above snippet is similar to its C++ counterpart. Here is a sample program demonstrating its use.





		
		
			How To Use Setw & Setfill
			
Java
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jun 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  Main.java
//    Description: Demonstrate the use of the Setw class
// ============================================================================
public class Main
{
    public static void main(String[] args)
    {
        // this formats text, printng whitespace to the right of the string
        System.out.print("1)");
        Setw.right("This is text right aligned", 45);
        System.out.println("");

        // this formats text, printng whitespace to the left of the string
        System.out.print("2)");
        Setw.left("This is text left aligned", 45);
        System.out.print("!");
        System.out.println("");

        // this formats text, but this time, instead of printng whitespace
        // to the left of the string, it prints a "filler," which can be anything
        // you want. Currently, the filler is a exclaimation ('!')
        System.out.print("3)");
        Setw.right("This is text right aligned with filler", 45, '!');
        System.out.println("");

        // this formats text, but this time, instead of printng whitespace
        // to the right of the string, it prints a "filler," which can be anything
        // you want. Currently, the filler is a dollar sign ('$')
        System.out.print("4)");
        Setw.left("This is text left aligned with filler", 45, '$');
        System.out.println("");

        // you can also send numbers to any of the functions,
        // provided you first convert them to strings
        System.out.print("5)");
        Setw.left("This is a string with a number " + Integer.toString(1987), 45, '.');
        System.out.println("\n");

        // you can also use this method to print the famous "triangle" shapes
        System.out.println("6) This is a triangle printed using the right method");
        for(int width = 0; width <= 10; ++width)
        {
            Setw.right("", width, '*');
            System.out.println("");
        }
        System.out.println("");

        // this prints an upside down triangle
        System.out.println("7) This is an upside down triangle printed "
                + "using the left method\n");
        for(int width = 10; width > 0; --width)
        {
            Setw.left("", width, '*');
            System.out.println("");
        }
        System.out.println("");

        // this is the example receipt
        System.out.println("8) This is the example receipt\n");
        Setw.left("Ending balance:", 32, '.');
        System.out.println(" $ " + Double.toString(6433.47));

        Setw.left("Amount of deposits:", 32, '.');
        System.out.println(" $ " + Double.toString(1750.00));

        Setw.left("Amount of withdrawals:", 32, '.');
        System.out.println(" $ " + Double.toString(420.00));

        Setw.left("Amount of interest earned:", 32, '.');
        System.out.println(" $ " + Double.toString(103.47));
    }// end of main
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jun 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  Main.java
//    Description: Demonstrate the use of the Setw class
// ============================================================================
public class Main
{
    public static void main(String[] args)
    {
        // this formats text, printng whitespace to the right of the string
        System.out.print("1)");
        Setw.right("This is text right aligned", 45);
        System.out.println("");
 
        // this formats text, printng whitespace to the left of the string
        System.out.print("2)");
        Setw.left("This is text left aligned", 45);
        System.out.print("!");
        System.out.println("");
 
        // this formats text, but this time, instead of printng whitespace
        // to the left of the string, it prints a "filler," which can be anything
        // you want. Currently, the filler is a exclaimation ('!')
        System.out.print("3)");
        Setw.right("This is text right aligned with filler", 45, '!');
        System.out.println("");
 
        // this formats text, but this time, instead of printng whitespace
        // to the right of the string, it prints a "filler," which can be anything
        // you want. Currently, the filler is a dollar sign ('$')
        System.out.print("4)");
        Setw.left("This is text left aligned with filler", 45, '$');
        System.out.println("");
 
        // you can also send numbers to any of the functions,
        // provided you first convert them to strings
        System.out.print("5)");
        Setw.left("This is a string with a number " + Integer.toString(1987), 45, '.');
        System.out.println("\n");
 
        // you can also use this method to print the famous "triangle" shapes
        System.out.println("6) This is a triangle printed using the right method");
        for(int width = 0; width <= 10; ++width)
        {
            Setw.right("", width, '*');
            System.out.println("");
        }
        System.out.println("");
 
        // this prints an upside down triangle
        System.out.println("7) This is an upside down triangle printed "
                + "using the left method\n");
        for(int width = 10; width > 0; --width)
        {
            Setw.left("", width, '*');
            System.out.println("");
        }
        System.out.println("");
 
        // this is the example receipt
        System.out.println("8) This is the example receipt\n");
        Setw.left("Ending balance:", 32, '.');
        System.out.println(" $ " + Double.toString(6433.47));
 
        Setw.left("Amount of deposits:", 32, '.');
        System.out.println(" $ " + Double.toString(1750.00));
 
        Setw.left("Amount of withdrawals:", 32, '.');
        System.out.println(" $ " + Double.toString(420.00));
 
        Setw.left("Amount of interest earned:", 32, '.');
        System.out.println(" $ " + Double.toString(103.47));
    }// end of main
}// http://programmingnotes.org/

Once compiled, you should get this as your output





		
		
			1)                   This is text right aligned
2)This is text left aligned                    !
3)!!!!!!!This is text right aligned with filler
4)This is text left aligned with filler$$$$$$$$
5)This is a string with a number 1987..........

6) This is a triangle printed using the right method

*
**
***
****
*****
******
*******
********
*********
**********

7) This is an upside down triangle printed using the left method

**********
*********
********
*******
******
*****
****
***
**
*

8) This is the example receipt

Ending balance:................. $ 6433.47
Amount of deposits:............. $ 1750.0
Amount of withdrawals:.......... $ 420.0
Amount of interest earned:...... $ 103.47
			
				
					
				
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						1)                   This is text right aligned
2)This is text left aligned                    !
3)!!!!!!!This is text right aligned with filler
4)This is text left aligned with filler$$$$$$$$
5)This is a string with a number 1987..........
 
6) This is a triangle printed using the right method
 
*
**
***
****
*****
******
*******
********
*********
**********
 
7) This is an upside down triangle printed using the left method
 
**********
*********
********
*******
******
*****
****
***
**
*
 
8) This is the example receipt
 
Ending balance:................. $ 6433.47
Amount of deposits:............. $ 1750.0
Amount of withdrawals:.......... $ 420.0
Amount of interest earned:...... $ 103.47

Java || Count The Total Number Of Characters, Vowels, & UPPERCASE Letters Contained In A Sentence Using A ‘For Loop’

June 04, 2012 admin No comments

Here is a simple program, which demonstrates more practice using the input/output mechanisms which are available in Java.

This program will prompt the user to enter a sentence, then upon entering an “exit code,” will display the total number of uppercase letters, vowels and characters which are contained within that sentence. This program is very similar to an earlier project, this time, utilizing a for loop, strings, and user defined methods.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

How To Get String Input If/Else Statements For Loops Methods (A.K.A "Functions") - What Are They?





		
		
			Count Characters, Vowels, & UPPERCASE Letters
			
Java
			
			import java.util.Scanner;

public class VowelCount
{
   public static void main(String[] args)
   {
	   // declare variables
	   int numUpperCase = 0;
	   int numVowel = 0;
	   int numChars = 0;
	   char character = ' '; 
	   String userInput= " ";
	   Scanner cin = new Scanner(System.in);
	   
	   // display message to screen
	   System.out.println("nWelcome to My Programming Notes' Java Program.");
	   
	   System.out.print("Enter a sentence, ending with a period: ");
	   userInput = cin.nextLine();	    
	   
	   // loop thru the string until we reach the 'exit code'
	   for(int index=0; userInput.charAt(index) != '.'; ++index)
	   {
		   character = userInput.charAt(index);

		   // do nothing, we dont care about whitespace
		   if(character == ' ')
		   {
			   continue;
		   }
		   
		   // check to see if entered data is UPPERCASE
		   if((character >= 'A')&&(character <= 'Z'))
		   {
			   ++numUpperCase; // Increments Total number of uppercase by one
		   } 
		   
		   // check to see if entered data is a vowel
		   if((character == 'a')||(character == 'A')||(character == 'e')||
				   (character == 'E')||(character == 'i')||(character == 'I')||
				   (character == 'o')||(character == 'O')||(character == 'u')||
				   (character == 'U')||(character == 'y')||(character == 'Y'))
		   {
			   ++numVowel; // increment total number of vowels by one
		   }
		
		   ++numChars;  // increment total number of chars by one
	   }
	   
	   setwf("ntTotal number of upper case letters:", 45,'.');	   
	   System.out.println(numUpperCase);
	   setwf("tTotal number of vowels:", 44,'.');
	   System.out.println(numVowel);
	   setwf("tTotal number of characters:", 44,'.');
	   System.out.println(numChars);
   }// end of main
   
   public static void setwf(String str, int width, char fill)
   {// this mimics the C++ 'setw' function & formats string output to the screen
	   System.out.print(str);
	   for (int x = str.length(); x < width; ++x) 
	   {
		   System.out.print(fill);			   
	   }
   }// end of setwf
}// http://programmingnotes.org/
			
				
					
				
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						import java.util.Scanner;
 
public class VowelCount
{
   public static void main(String[] args)
   {
	   // declare variables
	   int numUpperCase = 0;
	   int numVowel = 0;
	   int numChars = 0;
	   char character = ' '; 
	   String userInput= " ";
	   Scanner cin = new Scanner(System.in);
	   
	   // display message to screen
	   System.out.println("nWelcome to My Programming Notes' Java Program.");
	   
	   System.out.print("Enter a sentence, ending with a period: ");
	   userInput = cin.nextLine();	    
	   
	   // loop thru the string until we reach the 'exit code'
	   for(int index=0; userInput.charAt(index) != '.'; ++index)
	   {
		   character = userInput.charAt(index);
 
		   // do nothing, we dont care about whitespace
		   if(character == ' ')
		   {
			   continue;
		   }
		   
		   // check to see if entered data is UPPERCASE
		   if((character >= 'A')&&(character <= 'Z'))
		   {
			   ++numUpperCase; // Increments Total number of uppercase by one
		   } 
		   
		   // check to see if entered data is a vowel
		   if((character == 'a')||(character == 'A')||(character == 'e')||
				   (character == 'E')||(character == 'i')||(character == 'I')||
				   (character == 'o')||(character == 'O')||(character == 'u')||
				   (character == 'U')||(character == 'y')||(character == 'Y'))
		   {
			   ++numVowel; // increment total number of vowels by one
		   }
		
		   ++numChars;  // increment total number of chars by one
	   }
	   
	   setwf("ntTotal number of upper case letters:", 45,'.');	   
	   System.out.println(numUpperCase);
	   setwf("tTotal number of vowels:", 44,'.');
	   System.out.println(numVowel);
	   setwf("tTotal number of characters:", 44,'.');
	   System.out.println(numChars);
   }// end of main
   
   public static void setwf(String str, int width, char fill)
   {// this mimics the C++ 'setw' function & formats string output to the screen
	   System.out.print(str);
	   for (int x = str.length(); x < width; ++x) 
	   {
		   System.out.print(fill);			   
	   }
   }// end of setwf
}// http://programmingnotes.org/

QUICK NOTES:
The highlighted portions are areas of interest.

Notice line 22 contains the for loop declaration. The loop will continually loop thru the string, and will not stop doing so until it reaches an exit character, and the defined exit character in this program is a period (“.”). So, the program will not stop looping thru the string until it reaches a period.

Once compiling the above code, you should receive this as your output

Welcome to My Programming Notes' Java Program.
Enter a sentence, ending with a period: My Programming Notes Is An Awesome Site.
Total number of upper case letters:........7 Total number of vowels:....................14 Total number of characters:................33

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