While Loop

[ashonk226]

What do I need for a test expression in a while loop to keep the following loop running until the user inputs quit.

//Writing data to a file.
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>


using namespace std;

int main()
{
	ofstream outputFile;
	string firstName;
	string lastName;
	string phoneNumber;
	string quit;
	






	outputFile.open("phonebook.txt");




	while ( firstName !=  quit );
	{

		cout << "Enter your first name: " << endl;
		cin >> firstName;
		cout << "Enter your last name: " << endl;
		cin >> lastName;
		cout << "Enter the telephone number: " << endl;
		cin >> phoneNumber;
		cout << "The numbers were saved to a file. \n";


		//Write the names and phone number to a file.
		outputFile << firstName << " " << lastName << " " << phoneNumber << endl;

	}




	//Close the file.
	outputFile.close();
	cout << "Done. \n";
	system ("pause");
	return 0;
}

[adesh]

you can use

while (strcmp (firstName,"quit") != 0 ) //remove semicolon from here in your code

[vlad from moscow]

Without testing:

//Writing data to a file.
#include <iostream>
#include <fstream>
#include <string>
#include <iomanip>
#include <algorithm>
#include <cctype>

using namespace std;

int main()
{
	ofstream outputFile;

	outputFile.open("phonebook.txt");


	while ( outputFile )
	{
		const char quit[] = "QUIT";
		const size_t QUIT_SIZE = sizeof( quit ) -1;
		string firstName;
		string lastName;
		string phoneNumber;

		cout << "Enter your first name: " << endl;
		cin >> firstName;

		if ( firstName.size() == QUIT_SIZE && 
		     equal( firstName.begin(), firstName.end(), quit, []( char a, char b ) { return ( toupper(a ) == b ); } ) )
		{
			break;
		}

		cout << "Enter your last name: " << endl;
		cin >> lastName;
		cout << "Enter the telephone number: " << endl;
		cin >> phoneNumber;
		cout << "The numbers were saved to a file. \n";


		//Write the names and phone number to a file.
		outputFile << firstName << " " << lastName << " " << phoneNumber << endl;

	}




	//Close the file.
	outputFile.close();
	cout << "Done. \n";
	system ("pause");
	return 0;
}

EDIT: By the way in your original code there is a serious bug: presence of a semicolon after while

while ( firstName != quit );

[ashonk226]

I have 2 more quick questions. How can I format the number in the text file in the fashion as follows. [phone]
Also upon the user entering quit and the loop shutting down is it possible to display the contents of the file on the console.

Thank you for any help provided.

[Lim Boon Jye]

why don't u do cin.eof()?

do{
     ...
     ...
     cin >> input;
     if( cin.eof() ){
           cout << "you have quit the program " << endl;
     }
}while( !cin.eof() );

just some sample