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

February 26, 2012 admin No comments

The following is a palindrome checking program, which demonstrates more use of char array’s, ToUpper, Strlen, & Strcmp.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Character Arrays Cin.getline How to convert text in a char array from lower to uppercase How to reverse a character array Palindrome - What is it? Strlen Strcpy Strcmp While Loops For Loops Constant Variables Setw

Using a constant value, by default, this program first asks the user to enter 5 words and/or sentences that they want to compare for similarity. If the text which was entered into the program 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. This program also demonstrates how to reverse a character array, aswell as demonstrates how to convert all the text which was placed into the char array from lower to UPPERCASE.





		
		
			Palindrome Checker Using A Char Array
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 26, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Demonstrates a simple palindrome checker
// ============================================================================
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cctype>
#include <cstring>
using namespace std;

// constant value
const int NUM_WORDS = 5;

// function prototypes
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30]);
void ReverseCharArray(char palindrome[][30]);
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30]);

int main()
{
    // declare variable
    // this is a 2-D char array, which by default, has 
    // the ability to hold 5 names, each 30 characters long
    char words[NUM_WORDS][30];
    char wordsCopy[NUM_WORDS][30];
    char palindrome[NUM_WORDS][30];

    // get data from user
    cout << "\tWelcome to the Palindrome Check System!\n";
    cout << "\nPlease enter " << NUM_WORDS << " word(s) to check for similarity:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\t#" << index + 1 << ": ";
        cin.getline(words[index], 30);
    }

    // copy the user input into the 'wordsCopy' &
    // 'palindrome' char array
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        strcpy(wordsCopy[index], words[index]);
        strcpy(palindrome[index], words[index]);
    }

    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;

    // re-display the input to the screen
    cout << "\nThis is what you entered into the system:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\tText #" << index + 1 << ": " << words[index] << endl;
    }

    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;

    // function declaration
    // convert all the text contained in the 2 arrays to
    // UPPERCASE
    ConvertAllToUpper(wordsCopy, palindrome);

    // function declaration
    // reverses all the text contained inside the char array
    // to determine if it is a palindrome
    ReverseCharArray(palindrome);

    // display the palindrome's  to the screen
    cout << "\nHere are the palindrome's:\n";

    // function declaration
    // checks to see if the text contained in the char
    // array is a palindrome or not
    CheckIfPalindrome(wordsCopy, palindrome, words);

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

void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30])
{
    int index = 0;

    // increment thru the current char array index
    while (index < NUM_WORDS)
    {
        // increment thru each letter within the current char array index
        for (unsigned currentChar = 0; currentChar < strlen(wordsCopy[index]); ++currentChar)
        {
            // checks each letter in the current array index
            // to see if its lower or UPPERCASE
            // if its lowercase, change to UPPERCASE
            if (islower(wordsCopy[index][currentChar]))
            {
                wordsCopy[index][currentChar] = toupper(wordsCopy[index][currentChar]);
                palindrome[index][currentChar] = toupper(palindrome[index][currentChar]);
            }
        }
        ++index;
    }
}// end of ConvertAllToUpper

void ReverseCharArray(char palindrome[][30])
{
    int index = 0;

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

void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30])
{
    int palindromeCount = 0;

    // increment thru the current char array index
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        // if the contents in the 'wordsCopy' & 'palindrome'
        // are the same, then the word is a palindrome
        if (strcmp(wordsCopy[index], palindrome[index]) == 0)
        {
            cout << "\tText #" << index + 1 << ": " << words[index] << " is a palindrome" << endl;
            ++palindromeCount;
        }
    }
    if (palindromeCount == 0)
    {
        cout << "There were no palindrome's found in the current list!\n";
    }
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 26, 2012
//    Taken From: http://programmingnotes.org/
//    File:  palindrome.cpp
//    Description: Demonstrates a simple palindrome checker
// ============================================================================
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <cctype>
#include <cstring>
using namespace std;
 
// constant value
const int NUM_WORDS = 5;
 
// function prototypes
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30]);
void ReverseCharArray(char palindrome[][30]);
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30]);
 
int main()
{
    // declare variable
    // this is a 2-D char array, which by default, has 
    // the ability to hold 5 names, each 30 characters long
    char words[NUM_WORDS][30];
    char wordsCopy[NUM_WORDS][30];
    char palindrome[NUM_WORDS][30];
 
    // get data from user
    cout << "\tWelcome to the Palindrome Check System!\n";
    cout << "\nPlease enter " << NUM_WORDS << " word(s) to check for similarity:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\t#" << index + 1 << ": ";
        cin.getline(words[index], 30);
    }
 
    // copy the user input into the 'wordsCopy' &
    // 'palindrome' char array
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        strcpy(wordsCopy[index], words[index]);
        strcpy(palindrome[index], words[index]);
    }
 
    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;
 
    // re-display the input to the screen
    cout << "\nThis is what you entered into the system:\n";
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        cout << "\tText #" << index + 1 << ": " << words[index] << endl;
    }
 
    // create a line seperator
    cout << endl;
    cout.fill('-');
    cout << left << setw(30) << "" << right << setw(30) << "" << endl;
 
    // function declaration
    // convert all the text contained in the 2 arrays to
    // UPPERCASE
    ConvertAllToUpper(wordsCopy, palindrome);
 
    // function declaration
    // reverses all the text contained inside the char array
    // to determine if it is a palindrome
    ReverseCharArray(palindrome);
 
    // display the palindrome's  to the screen
    cout << "\nHere are the palindrome's:\n";
 
    // function declaration
    // checks to see if the text contained in the char
    // array is a palindrome or not
    CheckIfPalindrome(wordsCopy, palindrome, words);
 
    cin.get();
    return 0;
}// end of main
 
void ConvertAllToUpper(char wordsCopy[][30], char palindrome[][30])
{
    int index = 0;
 
    // increment thru the current char array index
    while (index < NUM_WORDS)
    {
        // increment thru each letter within the current char array index
        for (unsigned currentChar = 0; currentChar < strlen(wordsCopy[index]); ++currentChar)
        {
            // checks each letter in the current array index
            // to see if its lower or UPPERCASE
            // if its lowercase, change to UPPERCASE
            if (islower(wordsCopy[index][currentChar]))
            {
                wordsCopy[index][currentChar] = toupper(wordsCopy[index][currentChar]);
                palindrome[index][currentChar] = toupper(palindrome[index][currentChar]);
            }
        }
        ++index;
    }
}// end of ConvertAllToUpper
 
void ReverseCharArray(char palindrome[][30])
{
    int index = 0;
 
    // increment thru the current char array index
    while (index < NUM_WORDS)
    {    // get the length of the current word in the array index
        int wordLength = strlen(palindrome[index]) - 1;
        // increment thru each letter within the current char array index
        // reversing the order of the array
        for (int currentChar = 0; currentChar < wordLength; --wordLength, ++currentChar)
        {
            // copy 1st letter in the array index into temp
            char temp = palindrome[index][currentChar];
            // copy last letter in the array index into the 1st array index
            palindrome[index][currentChar] = palindrome[index][wordLength];
            // copy temp into last array index
            palindrome[index][wordLength] = temp;
        }
        ++index;
    }
}// end of ReverseCharArray
 
void CheckIfPalindrome(char wordsCopy[][30], char palindrome[][30], char words[][30])
{
    int palindromeCount = 0;
 
    // increment thru the current char array index
    for (int index = 0; index < NUM_WORDS; ++index)
    {
        // if the contents in the 'wordsCopy' & 'palindrome'
        // are the same, then the word is a palindrome
        if (strcmp(wordsCopy[index], palindrome[index]) == 0)
        {
            cout << "\tText #" << index + 1 << ": " << words[index] << " is a palindrome" << endl;
            ++palindromeCount;
        }
    }
    if (palindromeCount == 0)
    {
        cout << "There were no palindrome's found in the current list!\n";
    }
}// http://programmingnotes.org/

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

Click here to see how cin.getline works.

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 2 seperate times to demonstrate different output)

====== RUN 1 ======
Welcome to the Palindrome Check System! Please enter 5 word(s) to check for similarity: #1: SteP oN nO PEts #2: My ProGramminG NoTeS #3: RaTs liVE ON No eViL StaR #4: ABLe wAs I ErE I sAw ElBa #5: LiVE Non Evil ------------------------------------------------------------ This is what you entered into the system: Text #1: SteP oN nO PEts Text #2: My ProGramminG NoTeS Text #3: RaTs liVE ON No eViL StaR Text #4: ABLe wAs I ErE I sAw ElBa Text #5: LiVE Non Evil ------------------------------------------------------------ Here are the palindrome's: Text #1: SteP oN nO PEts is a palindrome Text #3: RaTs liVE ON No eViL StaR is a palindrome Text #4: ABLe wAs I ErE I sAw ElBa is a palindrome Text #5: LiVE Non Evil is a palindrome ====== RUN 2 ====== Welcome to the Palindrome Check System! Please enter 5 word(s) to check for similarity: #1: today Is Great #2: Tomorrow is Foriegn #3: Sunday Brunch #4: Hello SkiPper #5: Mayday Ship DowN! ------------------------------------------------------------ This is what you entered into the system: Text #1: today Is Great Text #2: Tomorrow is Foriegn Text #3: Sunday Brunch Text #4: Hello SkiPper Text #5: Mayday Ship DowN!
------------------------------------------------------------ Here are the palindrome's: There were no palindrome's found in the current list!

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Posted in: Basic, C++ Tags: array, c++, char, for loop, Output, Sentence, strcmp, strcpy, Text, While Loop

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

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