Thread: Problems validating

  1. #1
    Registered User
    Join Date
    May 2008
    Posts
    1

    Problems validating

    Hi, everyone. I am extremely new to C programming however, I have been programming VB for a few years now. I am stumped why I cannot get my code to work. It is very basic but I do not understand why the while loop executes even when it is false. Can someone help? Thank you in advance.

    Code:
    #include <stdio.h> 
    #include<system.h>
    #include <ctype.h>
    
    int main(void) 
    { 
    //*****Declare Tax, Tax Rate and Purchase Amount variables as double to handle large floating point numbers*********************** 
    double dSlsTaxD, dSlsTaxE, dSlsTaxL, dPurAmt, dSlsTaxRateD, dSlsTaxRateE, dSlsTaxRateL;
    //*****Declare user input variable as Integer because choices are 1 or 2**********************************************************
    int shouldContinue = 0; 
    //*****Declare validation variable as Character string that will handle 256 characters************************************************** 
    char garbage[256];
    //******************************************************************************************************************************** 
    
    //*****Initialize the variables***** 
       dPurAmt =  0; 
       dSlsTaxD =  0; 
       dSlsTaxE =  0; 
       dSlsTaxL =  0;   
       dSlsTaxRateD = .0725; // Sales Tax Rate for Del Mar store 
       dSlsTaxRateE = .0750; // Sales Tax Rate for Encinitas store 
       dSlsTaxRateL = .0775; // Sales Tax Rate for La Jolla store 
    //******************************************************************************************************************************** 
    
    	while((shouldContinue == 0));{
        	        printf("\n                     Please enter Purchase Amount: "); 
        		scanf("%lf", &dPurAmt); 
    
         				
        		if(scanf("%lf", &dPurAmt) != 1)  {  
        			shouldContinue = 0;
        			gets(garbage); 
        			printf("\nPlease enter a valid dollar amount without commas: ");
        			scanf("%lf", &dPurAmt); }
      			
    		 
        		else
        		    	shouldContinue = 1;
    		
     	   }
    
    
    
    //*****Calculate sales tax for individual stores***** 
       dSlsTaxD = dSlsTaxRateD * dPurAmt; 
       dSlsTaxE = dSlsTaxRateE * dPurAmt; 
       dSlsTaxL = dSlsTaxRateL * dPurAmt;   
    //*********************************************************************************************************************** 
    
    //*****Print results of calculation to the monitor***** 
       printf("\n                     For the purchase amount of $%.2f\n", dPurAmt); 
       printf("\nThe Del Mar store's sales tax will be:   $%.2f", dSlsTaxD); 
       printf("\nThe Encinitas store's sales tax will be: $%.2f", dSlsTaxE); 
       printf("\nThe La Jolla store's sales tax will be:  $%.2f", dSlsTaxL); 
    //***********************************************************************************************************************   
        
    //*****Forces the DOS prompt window to stay open because it is waiting for a key to be pressed*****   
       getch(); 
        
     //*****This line terminates the execution of the main function.***** 
       return 0; 
    }

  2. #2
    C++ Witch laserlight's Avatar
    Join Date
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    Location
    Singapore
    Posts
    28,413
    You have an extra semi-colon on this line:
    Code:
    while((shouldContinue == 0));{
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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