Need some coding help!!

[Gianmbaio]

Hey Guys (and Gals),

I am currently coding a receipt software. If the user gives bad input I have to make them give good input. They cant leave the program until good input is put. The input is Y/N, anything other than that is a wrong input. I know I have to use a "while" statement for this type of problem, i just dont know how. if you can help me I would highly appreciate it. THANKS!!!

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cstdlib>

using namespace std;

int main()

{
    float saleAmount;
    const float SALETAX = 0.07;
    float percentTip;
    float tipAmount;
    char input = ' ';

         
         
         cout << "Would you like to calculate a receipt? Y/N : ";
         cin >> input;


         
         switch (toupper(input)) 
       {   
         case 'Y':
         cout << endl << "WELCOME TO HAPPY TREE FRIENDS RESTAURANT " << endl << endl;
    
    
         cout << "Please enter sale amount: $ "; 
         cin >> saleAmount;
    
         cout << "Please enter tip percent: % ";
         cin >> percentTip;
    
         //Receipt
         cout << endl << setw(49) << "Happy Tree Friends Restaurant Customer Receipt " << endl;
    
         cout << endl << setw(43) << "-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*" << endl << endl;
         cout     << setw(38) << "Sale amount.............. " << setprecision(4) << saleAmount << endl;
         cout     << setw(38) << "Tip percent.............. " << percentTip << endl;
         cout     << setw(38) << "Tip amount............... " << percentTip * 100 << endl;
         cout     << setw(38) << "Tax Amount............... " << setprecision(2) << SALETAX << endl;
         cout <<endl << setw(38) << "Total.................... " << saleAmount + tipAmount + SALETAX << endl;
         cout << endl  << setw(43) << "-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*" << endl;

         break;
         
         case 'N':
       
         cout << "Thank you anyway. Please revisit the HAPPY TREE FRIENDS RESTAURANT " << endl;
         
         break;
         
       }
        
        


    
    
    
    ofstream outData;
    outData.open("output.txt");     
    
         outData << endl << setw(49) << "Happy Tree Friends Restaurant Customer Receipt " << endl;
    
         outData << endl << setw(43) << "-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*" << endl << endl;
    
         outData     << setw(38) << "Sale amount.............. " << setprecision(4)<< saleAmount << endl;
         outData     << setw(38) << "Tip percent.............. " << percentTip << endl;
         outData     << setw(38) << "Tip amount............... " << percentTip * 100 << endl;
         outData     << setw(38) << "Tax Amount............... " << SALETAX  << endl;
         outData <<endl << setw(38) << "Total.................... " << saleAmount + tipAmount + SALETAX << endl;

         outData << endl  << setw(43) << "-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*" << endl;       
         


    
    
    system("PAUSE");
    return EXIT_SUCCESS;

[superjacent]

Here's a snippet, I'm sure you'll get the idea and build upon it.

#include <iostream>
using namespace std;
int main()
{
    char keepgoing = 'Y';
    cout << "Do you want to continue <Y>es or <N>o : ";
    cin >> keepgoing;
    while (keepgoing == 'Y' || keepgoing == 'y')
    {
        cout << "\nDo stuff in here.....";
        cout << "\nDo you want to continue <Y>es or <N>o : ";
        cin >> keepgoing;
    }
    cout << "\n\nNow out of loop...";
}