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C++ || Class & Input/Output – Display The Contents Of A User Specified Text File To The Screen

April 24, 2012 admin No comments

The following is another intermediate homework assignment which was presented in a C++ programming course. This program was assigned to introduce more practice using the class data structure, which is very similar to the struct data structure.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Header Files - How To Use Them Class - What Is It? How To Read Data From A File String - Getline Array - Cin.Getline Strcpy - Copy Contents Of An Array #Define

This program first prompts the user to input a file name. After it obtains a file name from the user, it then attempts to display the contents of the user specified file to the output screen. If the file could not be found, an error message appears. If the file is found, the program continues as normal. After the file contents finishes being displayed, a summary indicating the total number of lines which has been read is also shown to the screen.

This program was implemented into 3 different files (two .cpp files, and one header file .h). So the code for this program will be broken up into 3 sections, the main file (.cpp), the header file (.h), and the implementation of the functions within the header file (.cpp).

Note: The data file that is used in this example can be downloaded here.

Also, in order to read in the data .txt file, you need to save the .txt file in the same directory (or folder) as your .cpp file is saved in. If you are using Visual C++, this directory will be located in

Documents > Visual Studio 2010 > Projects > [Your project name] > [Your project name]

======== FILE #1 – Main.cpp ========





		
		
			File #1 - Main.cpp
			
C++
			
			// ============================================================================
// File: Main.cpp 
// ============================================================================
// This program tests the "CFileDisp" object.  It prompts the user for an input
// filename, then attempts to display the contents of that file to stdout.
// After the file contents have been displayed, a summary line indicating the
// total number of lines that have been displayed is written to stdout.
// ============================================================================
#include <iostream>
#include <fstream>
#include "CFileDisp.h"
using namespace std;

// ==== main ==================================================================
//
// ============================================================================

int main()
{
	CFileDisp       myFile;
	char            fname[MAX_LENGTH];
	int             numLines;
	
	// get the filename from the user
	cout << "Enter a filename: ";
	cin.getline(fname, MAX_LENGTH);
	
	// copy the user's filename into the file object
	myFile.SetFilename(fname);
	
	// have the object open the file
	myFile.OpenFile();
	
	// if all is good and well...
	if(myFile.IsValid()==true)
	{
		numLines = myFile.DisplayFileContents();
		
		// close the file
		myFile.CloseFile();
		
		// write how many lines were displayed to stdout
		cout << "nt*** Total lines displayed: " << numLines << endl;
	}
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
// File: Main.cpp 
// ============================================================================
// This program tests the "CFileDisp" object.  It prompts the user for an input
// filename, then attempts to display the contents of that file to stdout.
// After the file contents have been displayed, a summary line indicating the
// total number of lines that have been displayed is written to stdout.
// ============================================================================
#include <iostream>
#include <fstream>
#include "CFileDisp.h"
using namespace std;
 
// ==== main ==================================================================
//
// ============================================================================
 
int main()
{
	CFileDisp       myFile;
	char            fname[MAX_LENGTH];
	int             numLines;
	
	// get the filename from the user
	cout << "Enter a filename: ";
	cin.getline(fname, MAX_LENGTH);
	
	// copy the user's filename into the file object
	myFile.SetFilename(fname);
	
	// have the object open the file
	myFile.OpenFile();
	
	// if all is good and well...
	if(myFile.IsValid()==true)
	{
		numLines = myFile.DisplayFileContents();
		
		// close the file
		myFile.CloseFile();
		
		// write how many lines were displayed to stdout
		cout << "nt*** Total lines displayed: " << numLines << endl;
	}
	
	return 0;
}// http://programmingnotes.org/

======== FILE #2 – CFileDisp.h ========

Remember, you need to name the header file the same as the #include from the Main.cpp file. This file contains the function declarations, but no implementation of those functions takes place here.





		
		
			File #2 - CFileDisp.h
			
C++
			
			// ============================================================================
// File: CFileDisp.h
// ============================================================================
// This is the header file which declares the objects which are used to open 
// a text file and display its contents to stdout.
// ============================================================================
#ifndef CFILE_DISP_HEADER
#define CFILE_DISP_HEADER

#include <fstream>
using namespace std;

#define MAX_LENGTH  256

class   CFileDisp
{
public:
	// constructor
	CFileDisp();
	
	// member functions
	void SetFilename(char  newFilename[]);
	/*  Purpose: Copy the user's filename into the file object */
	void OpenFile();
	/* Purpose: Open's the file which is specified by the user */
	bool IsValid();
	/* Purpose: Checks if the file exists. 
	   Post: Returns false if file cannot be found */
	int DisplayFileContents();
	/* Purpose: Display's the file contents to stdout
	   Post: Returns the total number of lines contained in the file */
	void CloseFile();
	/* Purpose: Closes the file */
	
	// destructor
	~CFileDisp();

private:
    bool            m_bIsValid;
    char            m_filename[MAX_LENGTH];
    ifstream        m_inFile;
};
#endif   // CFILE_DISP_HEADER // http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
// File: CFileDisp.h
// ============================================================================
// This is the header file which declares the objects which are used to open 
// a text file and display its contents to stdout.
// ============================================================================
#ifndef CFILE_DISP_HEADER
#define CFILE_DISP_HEADER
 
#include <fstream>
using namespace std;
 
#define MAX_LENGTH  256
 
class   CFileDisp
{
public:
	// constructor
	CFileDisp();
	
	// member functions
	void SetFilename(char  newFilename[]);
	/*  Purpose: Copy the user's filename into the file object */
	void OpenFile();
	/* Purpose: Open's the file which is specified by the user */
	bool IsValid();
	/* Purpose: Checks if the file exists. 
	   Post: Returns false if file cannot be found */
	int DisplayFileContents();
	/* Purpose: Display's the file contents to stdout
	   Post: Returns the total number of lines contained in the file */
	void CloseFile();
	/* Purpose: Closes the file */
	
	// destructor
	~CFileDisp();
 
private:
    bool            m_bIsValid;
    char            m_filename[MAX_LENGTH];
    ifstream        m_inFile;
};
#endif   // CFILE_DISP_HEADER // http://programmingnotes.org/

======== FILE #3 – CFileDisp.cpp ========

This is the function implementation file for the CFileDisp.h class. This file can be named anything you wish as long as you #include “CFileDisp.h”





		
		
			File #3 - CFileDisp.cpp
			
C++
			
			// ============================================================================
// File: CFileDisp.cpp
// ============================================================================
// This file implements the functions which are declared in the CFileDisp
// class, which is located in CFileDisp.h
// ============================================================================
#include <iostream>
#include <cstring>
#include <string>
#include "CFileDisp.h"
using namespace std;

CFileDisp::CFileDisp()
{
	m_bIsValid = 0;
}// end of CFileDisp

void CFileDisp::SetFilename(char  newFilename[])
{
    strcpy(m_filename,newFilename);
}// end of SetFilename

void CFileDisp::OpenFile()
{
	m_inFile.open(m_filename);
}// end of OpenFile

bool CFileDisp::IsValid()
{
	if (m_inFile.fail())
	{
		cout << m_filename << " was not found...nn";
		return false;
	}
	else 
	{
		return true;
	}
}// end of IsValid

int CFileDisp::DisplayFileContents()
{
	int total=0;
	string inLine;
	
	cout << endl;
	
	while(getline(m_inFile, inLine))
	{
		cout << inLine << endl;
		++total;
	}	
	return total;
}// end of DisplayFileContents

void CFileDisp::CloseFile()
{
	m_inFile.close();
}//	end of CloseFile

// this is the destructor
CFileDisp::~CFileDisp()
{
	m_bIsValid = 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
// File: CFileDisp.cpp
// ============================================================================
// This file implements the functions which are declared in the CFileDisp
// class, which is located in CFileDisp.h
// ============================================================================
#include <iostream>
#include <cstring>
#include <string>
#include "CFileDisp.h"
using namespace std;
 
CFileDisp::CFileDisp()
{
	m_bIsValid = 0;
}// end of CFileDisp
 
void CFileDisp::SetFilename(char  newFilename[])
{
    strcpy(m_filename,newFilename);
}// end of SetFilename
 
void CFileDisp::OpenFile()
{
	m_inFile.open(m_filename);
}// end of OpenFile
 
bool CFileDisp::IsValid()
{
	if (m_inFile.fail())
	{
		cout << m_filename << " was not found...nn";
		return false;
	}
	else 
	{
		return true;
	}
}// end of IsValid
 
int CFileDisp::DisplayFileContents()
{
	int total=0;
	string inLine;
	
	cout << endl;
	
	while(getline(m_inFile, inLine))
	{
		cout << inLine << endl;
		++total;
	}	
	return total;
}// end of DisplayFileContents
 
void CFileDisp::CloseFile()
{
	m_inFile.close();
}//	end of CloseFile
 
// this is the destructor
CFileDisp::~CFileDisp()
{
	m_bIsValid = 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





		
		
			Enter a filename: input_file_display_programmingnotes_freeweq_com.txt

346     130     982     90      656     117   595
415     948     126     4       558     571   87
42      360     412     721     463     47    119
441     190     985     214     509     2     571
77      81      681     651     995     93    74
310     9       995     561     92      14    288
466     664     892     8       766     34    639
151     64      98      813     67      834   369

                This is a line of text!

        *** Total lines displayed: 10
			
				
					
				
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						Enter a filename: input_file_display_programmingnotes_freeweq_com.txt
 
346     130     982     90      656     117   595
415     948     126     4       558     571   87
42      360     412     721     463     47    119
441     190     985     214     509     2     571
77      81      681     651     995     93    74
310     9       995     561     92      14    288
466     664     892     8       766     34    639
151     64      98      813     67      834   369
 
                This is a line of text!
 
        *** Total lines displayed: 10

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!

C++ || Char Array – Convert Text Contained In A Character Array From Lower To UPPERCASE

February 25, 2012 admin No comments

This program demonstrates how to switch text which is contained in a char array from lower to UPPERCASE. This program also demonstrates how to convert all of the text contained in a char array to lower/UPPERCASE.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Character Arrays Cin.getline Islower Isupper Tolower Toupper Strlen While Loops For Loops Constant Variables Setw

Using a constant integer value, this program first asks the user to enter in 3 lines of text they wish to convert from lower to UPPERCASE. Upon obtaining the information from the user, the program then converts all the text which was placed into the character array from lower to uppercase in the following order:

(1) Switches the text from lower to UPPERCASE (2) Converts all the text to UPPERCASE (3) Converts all the text to lowercase

After each conversion is complete, the program displays the updated information to the screen via cout.

NOTE: On some compilers, you may have to add #include < cstdlib>, #include < cctype>, and #include < cstring> in order for the code to compile.





		
		
			Convert Text From Lower To UPPERCASE
			
C++
			
			#include <iostream>
#include <iomanip>
using namespace std;

// constant value
const int NUM_NAMES = 3;

// function prototype
void ConvertLowerToUpper(char names[][30]);
void ConvertAllToUpper(char names[][30]);
void ConvertAllToLower(char names[][30]);

int main()
{
	// declare variable
	// this is a 2-D char array, which by default, has 
	// the ability to hold 3 names, each 30 characters long
	char names[NUM_NAMES][30];

	// get data from user
	cout << "Please enter "<<NUM_NAMES<<" line(s) of text you wish to convert from lower to UPPERCASE:nt";
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"#"<< index+1 <<": ";
		cin.getline(names[index],30);
		cout<< "t";
	}

	// 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:nt";
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}
	
	// create a line seperator
	cout<<endl;
	cout.fill('-');
	cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 

	// display the switched lower to UPPERCASE text to the user
	cout << "nThis is the information switched from lower to UPPERCASE:nt";
	
	// function declaration
	ConvertLowerToUpper(names);

	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}

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

	// display the 'all UPPERCASE' converted text to the user
	cout << "nThis is the information converted to all UPPERCASE:nt";
	
	// function declaration
	ConvertAllToUpper(names);

	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}

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

	// display the 'all lowercase' converted text to the user
	cout << "nThis is the information converted to all lowercase:nt";
	
	// function declaration
	ConvertAllToLower(names);

	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}

	return 0;
}// end of main

void ConvertLowerToUpper(char names[][30])
{
	int index=0;

	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[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(names[index][currentChar]))
			{
				names[index][currentChar] = toupper(names[index][currentChar]);
			}
			else  // if its UPPERCASE, change to lowercase
			{
				names[index][currentChar] = tolower(names[index][currentChar]);
			}
		}
		++index;
	}
}// end of ConvertLowerToUpper

void ConvertAllToUpper(char names[][30])
{
	int index=0;

	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[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(names[index][currentChar]))
			{
				names[index][currentChar] = toupper(names[index][currentChar]);
			}
		}
		++index;
	}
}// end of ConvertAllToUpper

void ConvertAllToLower(char names[][30])
{
	int index=0;

	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[index]); ++currentChar)
		{
			// checks each letter in the current array index
			// to see if its lower or UPPERCASE
			// if its UPPERCASE, change to lowercase
			if (isupper(names[index][currentChar]))
			{
				names[index][currentChar] = tolower(names[index][currentChar]);
			}
		}
		++index;
	}
}// http://programmingnotes.org/ 
			
				
					
				
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						#include <iostream>
#include <iomanip>
using namespace std;
 
// constant value
const int NUM_NAMES = 3;
 
// function prototype
void ConvertLowerToUpper(char names[][30]);
void ConvertAllToUpper(char names[][30]);
void ConvertAllToLower(char names[][30]);
 
int main()
{
	// declare variable
	// this is a 2-D char array, which by default, has 
	// the ability to hold 3 names, each 30 characters long
	char names[NUM_NAMES][30];
 
	// get data from user
	cout << "Please enter "<<NUM_NAMES<<" line(s) of text you wish to convert from lower to UPPERCASE:nt";
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"#"<< index+1 <<": ";
		cin.getline(names[index],30);
		cout<< "t";
	}
 
	// 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:nt";
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}
	
	// create a line seperator
	cout<<endl;
	cout.fill('-');
	cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 
 
	// display the switched lower to UPPERCASE text to the user
	cout << "nThis is the information switched from lower to UPPERCASE:nt";
	
	// function declaration
	ConvertLowerToUpper(names);
 
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}
 
	// create a line seperator
	cout<<endl;
	cout.fill('-');
	cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 
 
	// display the 'all UPPERCASE' converted text to the user
	cout << "nThis is the information converted to all UPPERCASE:nt";
	
	// function declaration
	ConvertAllToUpper(names);
 
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}
 
	// create a line seperator
	cout<<endl;
	cout.fill('-');
	cout<<left<<setw(30)<<""<<right<<setw(30)<<""<<endl; 
 
	// display the 'all lowercase' converted text to the user
	cout << "nThis is the information converted to all lowercase:nt";
	
	// function declaration
	ConvertAllToLower(names);
 
	for(int index=0; index < NUM_NAMES; ++index)
	{
		cout<<"Text #"<< index+1 <<": "<<names[index]<<endl;
		cout<< "t";
	}
 
	return 0;
}// end of main
 
void ConvertLowerToUpper(char names[][30])
{
	int index=0;
 
	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[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(names[index][currentChar]))
			{
				names[index][currentChar] = toupper(names[index][currentChar]);
			}
			else  // if its UPPERCASE, change to lowercase
			{
				names[index][currentChar] = tolower(names[index][currentChar]);
			}
		}
		++index;
	}
}// end of ConvertLowerToUpper
 
void ConvertAllToUpper(char names[][30])
{
	int index=0;
 
	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[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(names[index][currentChar]))
			{
				names[index][currentChar] = toupper(names[index][currentChar]);
			}
		}
		++index;
	}
}// end of ConvertAllToUpper
 
void ConvertAllToLower(char names[][30])
{
	int index=0;
 
	// increment thru the current char array index
	while(index < NUM_NAMES)
	{
		// increment thru each letter within the current char array index
		for(int currentChar=0;  currentChar < strlen(names[index]); ++currentChar)
		{
			// checks each letter in the current array index
			// to see if its lower or UPPERCASE
			// if its UPPERCASE, change to lowercase
			if (isupper(names[index][currentChar]))
			{
				names[index][currentChar] = tolower(names[index][currentChar]);
			}
		}
		++index;
	}
}// 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

Please enter 3 line(s) of text you wish to convert from lower to UPPERCASE: #1: I StriKe hiM a heAVy bloW. #2: When cAn the neRve ShinE? #3: My Programming Notes.
------------------------------------------------------------ This is what you entered into the system: Text #1: I StriKe hiM a heAVy bloW. Text #2: When cAn the neRve ShinE? Text #3: My Programming Notes. ------------------------------------------------------------ This is the information switched from lower to UPPERCASE: Text #1: i sTRIkE HIm A HEavY BLOw. Text #2: wHEN CaN THE NErVE sHINe? Text #3: mY pROGRAMMING nOTES. ------------------------------------------------------------ This is the information converted to all UPPERCASE: Text #1: I STRIKE HIM A HEAVY BLOW. Text #2: WHEN CAN THE NERVE SHINE? Text #3: MY PROGRAMMING NOTES.
------------------------------------------------------------ This is the information converted to all lowercase: Text #1: i strike him a heavy blow. Text #2: when can the nerve shine? Text #3: my programming notes.

C++ || Snippet – How To Read & Write Data From A File

February 12, 2012 admin No comments

This page will consist of a demonstration of a simple quadratic formula program, which highlights the use of the input/output mechanisms of manipulating a text file. This program will read in data from a file (numbers), manipulate that data, and output new data into a different text file.

REQUIRED KNOWLEDGE FOR THIS SNIPPET

Fstream Ifstream Ofstream Working With Files

NOTE: The data file that is used in this example can be downloaded here.

Documents > Visual Studio > Projects > [Your project name] > [Your project name]





		
		
			Input/Output Manipulation
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 12, 2012
//    Taken From: http://programmingnotes.org/
//    File:  FileInput.cpp
//    Description: Demonstrates how to read data from a file
// ============================================================================
#include <iostream>
#include <fstream>
#include <cstdlib> // used for the 'exit' command
#include <cmath>
using namespace std;

int main ()
{ 
	// declare variables
	ifstream infile;
	ofstream outfile;
	double a=0,b=0,c=0;
	double root1=0, root2=0;

	// this opens the input file
	// YOUR INPUT FILE NAME GOES BELOW
	infile.open("INPUT_Quadratic_programmingnotes_freeweq_com.txt");

	// check to see if the file even exists, & if not then EXIT
	if(infile.fail()) 
	{
		cout<<"\nError, the input file could not be found!\n";
		exit(1); // exits the program
	}

	// this opens the output file
	// if the file doesnt already exist, it will be created
	outfile.open("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt");

	// this loop reads in data until there is no more 
	// data contained in the file
	while(infile.good())
	{
		// this assigns the incoming data to the
		// variables 'a', 'b' and 'c'
		// NOTE: it is just like a cin >> statement
		infile >> a >> b >> c;

		// NOTE: if you want to read in data into an array
		// your declaration would be like this
		// ------------------------------------ 
		// infile >> a[counter] >> b[counter] >> c[counter];
		// ++counter;
	}

	// this does the quadratic formula calculations
	root1 = ((-b) + sqrt(pow(b,2) - (4*a*c)))/(2*a);
	root2 = ((-b) - sqrt(pow(b,2) - (4*a*c)))/(2*a);

	// this displays the numbers to screen via cout
	cout <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	cout <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
	
	// this saves the data to the output file
	// NOTE: its almost exactly the same as the cout statement
	outfile <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	outfile <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;

	// close the input/output files once you are done using them
	infile.close();
	outfile.close();

	// stops the program from automatically closing
	cin.get();

	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Feb 12, 2012
//    Taken From: http://programmingnotes.org/
//    File:  FileInput.cpp
//    Description: Demonstrates how to read data from a file
// ============================================================================
#include <iostream>
#include <fstream>
#include <cstdlib> // used for the 'exit' command
#include <cmath>
using namespace std;
 
int main ()
{ 
	// declare variables
	ifstream infile;
	ofstream outfile;
	double a=0,b=0,c=0;
	double root1=0, root2=0;
 
	// this opens the input file
	// YOUR INPUT FILE NAME GOES BELOW
	infile.open("INPUT_Quadratic_programmingnotes_freeweq_com.txt");
 
	// check to see if the file even exists, & if not then EXIT
	if(infile.fail()) 
	{
		cout<<"\nError, the input file could not be found!\n";
		exit(1); // exits the program
	}
 
	// this opens the output file
	// if the file doesnt already exist, it will be created
	outfile.open("OUTPUT_Quadratic_programmingnotes_freeweq_com.txt");
 
	// this loop reads in data until there is no more 
	// data contained in the file
	while(infile.good())
	{
		// this assigns the incoming data to the
		// variables 'a', 'b' and 'c'
		// NOTE: it is just like a cin >> statement
		infile >> a >> b >> c;
 
		// NOTE: if you want to read in data into an array
		// your declaration would be like this
		// ------------------------------------ 
		// infile >> a[counter] >> b[counter] >> c[counter];
		// ++counter;
	}
 
	// this does the quadratic formula calculations
	root1 = ((-b) + sqrt(pow(b,2) - (4*a*c)))/(2*a);
	root2 = ((-b) - sqrt(pow(b,2) - (4*a*c)))/(2*a);
 
	// this displays the numbers to screen via cout
	cout <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	cout <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
	
	// this saves the data to the output file
	// NOTE: its almost exactly the same as the cout statement
	outfile <<"For the numbers\na = "<<a<<"\nb = "<<b<<"\nc = "<<c<<endl;
	outfile <<"\nroot 1 = "<<root1<<"\nroot 2 = "<<root2<<endl;
 
	// close the input/output files once you are done using them
	infile.close();
	outfile.close();
 
	// stops the program from automatically closing
	cin.get();
 
	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

For the numbers a = 2 b = 4 c = -16
root 1 = 2 root 2 = -4

C++ || Input/Output – Find The Average of The Numbers Contained In a Text File Using an Array/Bubble Sort

January 31, 2012 admin No comments

This program highlights more practice using text files and arrays. This program is very similar to one which was previously discussed on this site, but unlike that program, this implementation omits the highest/lowest values which are found within the array via a sort.

The previously discussed program works almost as well as the current implementation, but where it fails is when the data which is being entered into the program contains multiple values of the same type. For example, using the previously discussed method to obtain the average by omitting the highest/lowest entries found within an array, if the array contained the numbers:

1, 2, 3, 3, 3, 2, 2, 1

The previous implementation would mark 1 as being the lowest number (which is correct) and it would mark 3 as being the highest number (which is also correct). The area where it fails is when it omits the highest and lowest scores found within the array. The program will skip over ALL of the numbers contained within the array which equal to 1 and 3, thus resulting in the program obtaining the wrong answer.

To illustrate, before the previous program computes its adjusted average scores, it will not only omit just 1 and 3 from the array, but it will also omit all of the 1’s and 3’s from the list, resulting in our array looking like this:

2, 2, 2

When you are finding the average of a list of numbers by omitting the highest/lowest scores, you don’t want to omit ALL of the values which may equal said numbers, but merely just the highest (last element in the array) and lowest (first element in the array) scores.

So if the previous implementation has subtle issues, why is it on this site? The previous program illustrates very well the process of finding the highest/lowest integers found within an array. It also works flawlessly for data in which there is non repeating values found within a list (i.e 1,2,3,4,5,23,6). So if you know you are reading in from a file in which there are non repeating values, the previous implementation works well. Often times though, developers do not know what type of data the incoming files will contain, so this current implementation is a better way to go, especially if it is not known exactly how many numbers are contained within a file.

REQUIRED KNOWLEDGE FOR THIS PROGRAM

Fstream Ifstream Ofstream Working With Files While Loops For Loops Bubble Sort Basic Math - Finding The Average

The data file that is used in this example can be downloaded here.

Note: In order to read in the data .txt file, you need to save the .txt file in the same directory (or folder) as your .cpp file is saved in. If you are using Visual C++, this directory will be located in

Documents > Visual Studio 2010 > Projects > [Your project name] > [Your project name]

NOTE: On some compilers, you may have to add #include < cstdlib> in order for the code to compile.





		
		
			Omit The Highest/Lowest Numbers In Array via Bubble Sort
			
C++
			
			#include <iostream>
#include <fstream>
using namespace std;

// function prototype
float FindOmittedAverage(int numbers[], int counter);

int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
	float average=0;
	float sum =0;
	int highestNumber = -999999;
	int lowestNumber = 99999999;
	int numbers[100];

	// open the input file in which you will read data from
	infile.open("INPUT_Numbers_ programmingnotes_freeweq_com.txt");
	if(infile.fail())
	{
		cout<<"nInput file not found!n";
		exit(1); // there was an error, program exits
	}

	// open the output file in  which the compiled data will be saved to
	outfile.open("OUTPUT_Averages_ programmingnotes_freeweq_com.txt");
	if(outfile.fail())
	{
		cout <<"There was an error creating the output file, press enter to terminate program.";
		exit(1); // there was an error, program exits
	} 

	// display data to screen via cout
	cout <<"The numbers countained in the input file are: ";

	// saves data to the outfile. Notice the declaration to
	// save data to the outfile is the same as the ^ above cout
	// statment
	outfile <<"The numbers countained in the input file are: ";

	// incoming data from the file will be stored in an int array
	// so this counter will increment the array index every time the
	// program finds a new value inside the file to store inside the array
	int counter =0;

	// this while loop will read in data from the file until it reaches the end of the file
	// (i.e until there are no more number found within the file)
	// this process also stored the numbers inside the "numbers" array
	while(infile >> numbers[counter])
	{
		// 'sum' variable adds the incoming numbers together
		// computing the sum
		sum += numbers[counter];

		// finds the highest number contained within the incoming file
		if( numbers[counter] > highestNumber)
		{
			highestNumber = numbers[counter];
		}

		// finds the lowest number contained within the incoming file
		if (numbers[counter] < lowestNumber)
		{
			lowestNumber = numbers[counter];
		}

		// displays the currently found number from the file to stdout
		cout << numbers[counter] << ", ";

		// saves the currently found number from the file to the output file
		outfile << numbers[counter]<< ", ";
		++counter;
	}
	// always close your file after your done using them
	infile.close();

	// display the highest found number to stdout
	cout<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;

	// saves the highest found number to the output file
	outfile<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;

	// using the sum found from the above while loop, we compute the average
	average = sum/(counter);

	// display/save the average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;

	// function declaration which finds the omitted average of the found numbers
	// from the file
	average = FindOmittedAverage(numbers,counter);

	// display/save the omitted average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;

	// closes the outfile once we are done using it
	outfile.close();

	return 0;
}

// function takes in the 'numbers' array, and 'counter' variable from
// the main function as parameters, and computes the average, omitting 
// the highest and lowest numbers found within the array
float FindOmittedAverage(int numbers[], int counter)
{
	float sum = 0;
	float avg = 0;

	// this is a 'bubble sort' which will sort the numbers
	// contained within the array, from lowest to the highest 
	// i.e (1,2,3,4,5,6,7,8)
	for(int iteration = 1; iteration < counter; iteration++)
	{
		for(int index = 0; index < counter - iteration; index++)
		{
		// if the previous value in the array is bigger than the next, then swap them
			if(numbers[index]> numbers[index+1]) 
			{
				int temp = numbers[index];
				numbers[index] = numbers[index+1];
				numbers[index+1]= temp;
			}
		}
	}// end of sort

	// after the sorting is complete, set the highest 
	// and lowest elements in the array to zero
	numbers[0]=0;
	numbers[counter-1]=0;

	// find the sum of the newly sorted array
	// with the highest and lowest entries being deleted (set to zero)
	for(int i = 0; i < counter; i++)
	{
		sum += numbers[i];
	}

	// compute the average
	avg = sum / (counter-2);

	// return the average back to main
	return avg;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <fstream>
using namespace std;
 
// function prototype
float FindOmittedAverage(int numbers[], int counter);
 
int main()
{
	// declare variables
	ifstream infile;
	ofstream outfile;
	float average=0;
	float sum =0;
	int highestNumber = -999999;
	int lowestNumber = 99999999;
	int numbers[100];
 
	// open the input file in which you will read data from
	infile.open("INPUT_Numbers_ programmingnotes_freeweq_com.txt");
	if(infile.fail())
	{
		cout<<"nInput file not found!n";
		exit(1); // there was an error, program exits
	}
 
	// open the output file in  which the compiled data will be saved to
	outfile.open("OUTPUT_Averages_ programmingnotes_freeweq_com.txt");
	if(outfile.fail())
	{
		cout <<"There was an error creating the output file, press enter to terminate program.";
		exit(1); // there was an error, program exits
	} 
 
	// display data to screen via cout
	cout <<"The numbers countained in the input file are: ";
 
	// saves data to the outfile. Notice the declaration to
	// save data to the outfile is the same as the ^ above cout
	// statment
	outfile <<"The numbers countained in the input file are: ";
 
	// incoming data from the file will be stored in an int array
	// so this counter will increment the array index every time the
	// program finds a new value inside the file to store inside the array
	int counter =0;
 
	// this while loop will read in data from the file until it reaches the end of the file
	// (i.e until there are no more number found within the file)
	// this process also stored the numbers inside the "numbers" array
	while(infile >> numbers[counter])
	{
		// 'sum' variable adds the incoming numbers together
		// computing the sum
		sum += numbers[counter];
 
		// finds the highest number contained within the incoming file
		if( numbers[counter] > highestNumber)
		{
			highestNumber = numbers[counter];
		}
 
		// finds the lowest number contained within the incoming file
		if (numbers[counter] < lowestNumber)
		{
			lowestNumber = numbers[counter];
		}
 
		// displays the currently found number from the file to stdout
		cout << numbers[counter] << ", ";
 
		// saves the currently found number from the file to the output file
		outfile << numbers[counter]<< ", ";
		++counter;
	}
	// always close your file after your done using them
	infile.close();
 
	// display the highest found number to stdout
	cout<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;
 
	// saves the highest found number to the output file
	outfile<< "nnThe highest and lowest numbers contained in the file are: nHighest: "
		<< highestNumber<<"nLowest: "<<lowestNumber<<endl;
 
	// using the sum found from the above while loop, we compute the average
	average = sum/(counter);
 
	// display/save the average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file is: "<<average<<endl;
 
	// function declaration which finds the omitted average of the found numbers
	// from the file
	average = FindOmittedAverage(numbers,counter);
 
	// display/save the omitted average of the numbers which were contained in the 
	// file to stdout and the output file
	cout<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
	outfile<<"nThe average of the "<<counter<<" numbers contained in the file omitting the highest and lowest scores is: "<<average<<endl;
 
	// closes the outfile once we are done using it
	outfile.close();
 
	return 0;
}
 
// function takes in the 'numbers' array, and 'counter' variable from
// the main function as parameters, and computes the average, omitting 
// the highest and lowest numbers found within the array
float FindOmittedAverage(int numbers[], int counter)
{
	float sum = 0;
	float avg = 0;
 
	// this is a 'bubble sort' which will sort the numbers
	// contained within the array, from lowest to the highest 
	// i.e (1,2,3,4,5,6,7,8)
	for(int iteration = 1; iteration < counter; iteration++)
	{
		for(int index = 0; index < counter - iteration; index++)
		{
		// if the previous value in the array is bigger than the next, then swap them
			if(numbers[index]> numbers[index+1]) 
			{
				int temp = numbers[index];
				numbers[index] = numbers[index+1];
				numbers[index+1]= temp;
			}
		}
	}// end of sort
 
	// after the sorting is complete, set the highest 
	// and lowest elements in the array to zero
	numbers[0]=0;
	numbers[counter-1]=0;
 
	// find the sum of the newly sorted array
	// with the highest and lowest entries being deleted (set to zero)
	for(int i = 0; i < counter; i++)
	{
		sum += numbers[i];
	}
 
	// compute the average
	avg = sum / (counter-2);
 
	// return the average back to main
	return avg;
}// 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
(Remember to include the input file)

The numbers countained in the input file are: 12, 45, 23, 46, 11, -5, 23, 33, 50, 17, 13, 25, 15, 50, The highest and lowest numbers contained in the file are: Highest: 50 Lowest: -5
The average of the 14 numbers contained in the file is: 25.5714 The average of the 14 numbers contained in the file omitting the highest and lowest scores is: 26.0833

C++ || Input/Output Text File Manipulation – Find Highest, Lowest, Average & Total Sum

January 06, 2012 admin No comments

This is a program which will utilize fstream, specifically ifstream and ofstream, to read in data from one .txt file, and it will then output selected data into an entirely new separate .txt file.

The input data file has 8 different rows, with each row containing 7 numbers on each line. The program will take in each line one at a time, manipulating the 7 numbers to receive the desired output. This program will find the highest/lowest number in each selected line, along with the total sum of all the numbers contained in that line, and the average of all the numbers. So at the end of the program, There will be 8 different sets of data compiled for each row, with the output file looking like this:

SAMPLE RUN:
- Input File - 3 5 7 3 4 5 6
- Output File - The dataset for input line #1 is: 3 5 7 3 4 5 6 The highest number is: 7 The lowest number is: 3 The total of the numbers is: 33 The average of the numbers is: 4.71

The data file that is used in this example can be downloaded here

Documents > Visual Studio > Projects > [Your project name] > [Your project name]

NOTE: On some compilers, you may have to add #include < cstdlib> in order for the code to compile.





		
		
			Text File Manipulation
			
C++
			
			// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  fileInput.cpp
//    Description: Demonstrates how to read and write data to a file
// ============================================================================
#include <iostream>
#include <fstream>
using namespace std;

int main ()
{   // declare variables
    ifstream infile;
    ofstream outfile;
    int inputNumber = 0;
    int highestNum = -999999;
    int lowestNum = 999999;
    double sum = 0;
    double average = 0;
    int currentLineNum = 1;     
     
    // This opens the input file
    infile.open("INPUT_programmingnotes_freeweq_com.txt");
    if(infile.fail()) //there was an error on open, file not found
    {
        cout << "Cannot find input file, press enter to terminate program." << endl;
        exit (1); // there was an error, program exits
    }

    // This opens the output file
    outfile.open("OUTPUT_programmingnotes_freeweq_com.txt", ios::app);
    if(outfile.fail())
    {
        cout <<"There was an error opening the output file, press enter to terminate program.";
        exit(1); // there was an error, program exits
    }

    do {
        cout << "The dataset for input line #" << currentLineNum << " is: ";
        outfile << "The dataset for input line #" << currentLineNum << " is: ";

        // loops thru file until we get to the last number 
        // from the selected line 
        // (theres 7 numbers total in each line, see input file for clarification)
        for(int counter = 1; counter <= 7; counter++)
        {   
            infile >> inputNumber;

            sum += inputNumber;  // calculates the total sum of #'s for each line

            // checks to see which number is highest/lowest from 
            // each selected line
            if(inputNumber > highestNum)
            {
                highestNum = inputNumber;
            }

            if(inputNumber < lowestNum)
            {
                lowestNum = inputNumber;
            }

            // displays current number to output screen
            // and saves to file
            cout << inputNumber << "\t";
            outfile << inputNumber << "\t";
        }// end for loop

        average = sum / 7; // finds the total avg for each line

        // this displays data to the output screen
        cout << endl;
        cout << "The highest number is: " << highestNum << endl;
        cout << "The lowest number is: " << lowestNum << endl;
        cout << "The total of the numbers is: " << sum << endl;
        cout << "The average of the numbers is: " << average << endl;

        // outfile section here, saves data to file
        outfile << endl;
        outfile << "The highest number is: " << highestNum << endl;
        outfile << "The lowest number is: " << lowestNum << endl;
        outfile << "The total of the numbers is: " << sum << endl;
        outfile << "The average of the numbers is: " << average << endl << endl;
        // outfile section end

        // resets variables back to default values
        highestNum = -999999;
        lowestNum = 999999;
        sum = 0;
        average = 0;
        currentLineNum++;

        // places data on new line
        cout << endl << endl;    

    } while(!infile.eof()); // loop stops once it reaches the end of file
    
    cout << endl << endl <<"\tWe have reached the end of the file!"<< endl;
    outfile << endl << endl <<"\tWe have reached the end of the file!"<< endl << endl;
    outfile.close();  // closes outfile
    infile.close();        // closes infile

    return 0;
}// http://programmingnotes.org/
			
				
					
				
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						// ============================================================================
//    Author: Kenneth Perkins
//    Date:   Jan 6, 2012
//    Taken From: http://programmingnotes.org/
//    File:  fileInput.cpp
//    Description: Demonstrates how to read and write data to a file
// ============================================================================
#include <iostream>
#include <fstream>
using namespace std;
 
int main ()
{   // declare variables
    ifstream infile;
    ofstream outfile;
    int inputNumber = 0;
    int highestNum = -999999;
    int lowestNum = 999999;
    double sum = 0;
    double average = 0;
    int currentLineNum = 1;     
     
    // This opens the input file
    infile.open("INPUT_programmingnotes_freeweq_com.txt");
    if(infile.fail()) //there was an error on open, file not found
    {
        cout << "Cannot find input file, press enter to terminate program." << endl;
        exit (1); // there was an error, program exits
    }
 
    // This opens the output file
    outfile.open("OUTPUT_programmingnotes_freeweq_com.txt", ios::app);
    if(outfile.fail())
    {
        cout <<"There was an error opening the output file, press enter to terminate program.";
        exit(1); // there was an error, program exits
    }
 
    do {
        cout << "The dataset for input line #" << currentLineNum << " is: ";
        outfile << "The dataset for input line #" << currentLineNum << " is: ";
 
        // loops thru file until we get to the last number 
        // from the selected line 
        // (theres 7 numbers total in each line, see input file for clarification)
        for(int counter = 1; counter <= 7; counter++)
        {   
            infile >> inputNumber;
 
            sum += inputNumber;  // calculates the total sum of #'s for each line
 
            // checks to see which number is highest/lowest from 
            // each selected line
            if(inputNumber > highestNum)
            {
                highestNum = inputNumber;
            }
 
            if(inputNumber < lowestNum)
            {
                lowestNum = inputNumber;
            }
 
            // displays current number to output screen
            // and saves to file
            cout << inputNumber << "\t";
            outfile << inputNumber << "\t";
        }// end for loop
 
        average = sum / 7; // finds the total avg for each line
 
        // this displays data to the output screen
        cout << endl;
        cout << "The highest number is: " << highestNum << endl;
        cout << "The lowest number is: " << lowestNum << endl;
        cout << "The total of the numbers is: " << sum << endl;
        cout << "The average of the numbers is: " << average << endl;
 
        // outfile section here, saves data to file
        outfile << endl;
        outfile << "The highest number is: " << highestNum << endl;
        outfile << "The lowest number is: " << lowestNum << endl;
        outfile << "The total of the numbers is: " << sum << endl;
        outfile << "The average of the numbers is: " << average << endl << endl;
        // outfile section end
 
        // resets variables back to default values
        highestNum = -999999;
        lowestNum = 999999;
        sum = 0;
        average = 0;
        currentLineNum++;
 
        // places data on new line
        cout << endl << endl;    
 
    } while(!infile.eof()); // loop stops once it reaches the end of file
    
    cout << endl << endl <<"\tWe have reached the end of the file!"<< endl;
    outfile << endl << endl <<"\tWe have reached the end of the file!"<< endl << endl;
    outfile.close();  // closes outfile
    infile.close();        // closes infile
 
    return 0;
}// http://programmingnotes.org/

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

LOOPS
This program utilizes one do/while loop on lines 39-97 which loops thru the input file until it reaches the end of the file. This program also uses a for loop, which is noted on line 46.

CALCULATING THE SUM
Line 50 contains the assignment operator “+=“, which will calculate a running total for all the values of each selected line.

READING IN DATA FROM FILE
This is noted in line 48, and works just like a cin statement.

OPENING FILES
File declarations, and the opening of files are highlighted on lines: 14-15, 24-25, 32-33. On line 32, the term “ios::app” means the file will append new data to the text file, instead of overwriting the old data contained within that file.

OUTPUT DATA TO FILE
This is highlighted on lines 80-84, and as you can see, the output statements are exactly the same as cout statements.

CLOSE FILES
Remember to close the files you open, as highlighted on lines 101 and 102.

Once compiling the above code, you should receive this as your output (for the 8 selected lines contained within the input text file)

The dataset for input line #1 is: 346 130 982 90 656 117 595 The highest number is: 982 The lowest number is: 90 The total of the numbers is: 2916 The average of the numbers is: 416.571
The dataset for input line #2 is: 415 948 126 4 558 571 87 The highest number is: 948 The lowest number is: 4 The total of the numbers is: 2709 The average of the numbers is: 387 The dataset for input line #3 is: 42 360 412 721 463 47 119 The highest number is: 721 The lowest number is: 42 The total of the numbers is: 2164 The average of the numbers is: 309.143 The dataset for input line #4 is: 441 190 985 214 509 2 571 The highest number is: 985 The lowest number is: 2 The total of the numbers is: 2912 The average of the numbers is: 416 The dataset for input line #5 is: 77 81 681 651 995 93 74 The highest number is: 995 The lowest number is: 74 The total of the numbers is: 2652 The average of the numbers is: 378.857 The dataset for input line #6 is: 310 9 995 561 92 14 288 The highest number is: 995 The lowest number is: 9 The total of the numbers is: 2269 The average of the numbers is: 324.143 The dataset for input line #7 is: 466 664 892 8 766 34 639 The highest number is: 892 The lowest number is: 8 The total of the numbers is: 3469 The average of the numbers is: 495.571 The dataset for input line #8 is: 151 64 98 813 67 834 369 The highest number is: 834 The lowest number is: 64 The total of the numbers is: 2396 The average of the numbers is: 342.286
We have reached the end of the file!

Tag Archives: Text

C++ || Class & Input/Output – Display The Contents Of A User Specified Text File To The Screen

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

C++ || Char Array – Convert Text Contained In A Character Array From Lower To UPPERCASE

C++ || Snippet – How To Read & Write Data From A File

C++ || Input/Output – Find The Average of The Numbers Contained In a Text File Using an Array/Bubble Sort

C++ || Input/Output Text File Manipulation – Find Highest, Lowest, Average & Total Sum

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