Thread: "Do While" loop

I'm trying to modify the program. So, the user inputs the purchase
amount and the program checks the users input for validity. HELP I need today!!

Code:

 
/*
Program: Kudler Tax Calculation Program
SR-kf-008
Date: August 11, 2006 
 
Author: Douglas Niemczynski 
 
*/
 
#include <stdio.h> 
 
void main()
 
{
    float fDelMar = 0.0725f;              // tax for Del Mar
    float fEncinitas = 0.0750f;         // tax for Encinitas
    float fLaJolla = 0.0775f;           // tax for La Jolla
    float fPurchaseAmount = 0.0f;       // amount of purchase
    float fTax = 0.0f;                          // taxes
    float fTotal = 0.0f;
    int iStoreChoice = 0;               // menu selection
                  
 
    // print menu
    printf("\n1 - Del Mar");
    printf("\n2 - Encinitas");
    printf("\n3 - La Jolla");
    printf ("\nSelect city number 1, 2, or 3\n");
 
    printf("\nEnter your selection: ");
    scanf("%d", &iStoreChoice);
 
    printf("\n\nEnter Purchase Amount: ");
    scanf("%f", &fPurchaseAmount);
       
            
    // apply taxes for purchase ammount
    switch (iStoreChoice)
    {
    case 1:
        fTax = fPurchaseAmount * fDelMar;
        break;
    case 2:
        fTax = fPurchaseAmount  * fEncinitas;
        break;
    case 3:
        fTax = fPurchaseAmount  * fLaJolla;
        break;
    }
 
    fTotal = fPurchaseAmount + fTax;
 
    // print out
    printf("Purchase Price:\t%.2f", fPurchaseAmount);
    printf("\nTotal price after taxes of (%.2f) is %.2f\n", fTax, fTotal);  
    printf("\nPress ENTER to Quit\n");
    fflush(stdin);
    getchar();          
}

What is the deal? We won't code for you, we can help you. Where specifically in this source is your problem?