Thread: Try again decision problem

Hi guys! can you help a novice programmer here. I've been working on a Try again decision using the Do-While loop. Heres the code I've established.

Code:

#include <stdio.h>

int main(void)

{


// Declaration of Variables
double Pounds = 0;
double Kilograms = 0;
double Inches = 0;
double Meters = 0;
double BMI = 0;

char ans1 = ' ';
char ans2 = ' ';
char ans3 = ' ';


    do
    {
        {
        printf("Please enter your height(Meters): ");
        scanf("%lf", &Meters);
            
        printf("Please enter your weight(Kilograms): ");
        scanf("%lf", &Kilograms);
            
        BMI = Kilograms/(Meters*Meters);
            
        printf("Your BMI (Meters&Kilograms) is: %.2f\n", BMI);
        }
    
    printf("Would you like to try again? (y/n): ");
    scanf("%c", &ans1);
    fflush(stdin);
    }
    while (ans1 =='y');
    
}

The whole thing works until I reach the try again decision.

Code:

Please enter your height(Meters): 
1.6
Please enter your weight(Kilograms): 
52
Your BMI (Inches&Pounds) is: 20.31
Would you like to try again? (y/n): 
Program ended with exit code: 0

This is what I always end up with. I would really appreciate the help

Call fflush(stdin) before every scanf()

Originally Posted by DRK

Call fflush(stdin) before every scanf()

No! Never call fflush(stdin). Read this link: FAQ > Why fflush(stdin) is wrong - Cprogramming.com.

@OP:
Note, when you hit enter, like you do after entering your height/weith, that puts a new line ('\n') in the input buffer. scanf, when used with the %c, doesn't skip leading white space like the other modifiers (%d, %lf, etc) do. That means when you scan a char into ans1, you scan in the '\n'. You can force scanf to skip any leading whitespace, including '\n', by putting a space before the %c, like scanf(" %c", &ans1).

Sorry, my advice wasn't correct, I was sugested by fflush(stdin) already used in the example code.

Originally Posted by anduril462

No! Never call fflush(stdin). Read this link: FAQ > Why fflush(stdin) is wrong - Cprogramming.com.

@OP:
Note, when you hit enter, like you do after entering your height/weith, that puts a new line ('\n') in the input buffer. scanf, when used with the %c, doesn't skip leading white space like the other modifiers (%d, %lf, etc) do. That means when you scan a char into ans1, you scan in the '\n'. You can force scanf to skip any leading whitespace, including '\n', by putting a space before the %c, like scanf(" %c", &ans1).

Got it! Thanks for the help dude!

Code:

Please enter your height(Meters): 1.62
Please enter your weight(Kilograms): 59
Your BMI (Inches&Pounds) is: 22.48
Would you like to try again? (y/n): y
Please enter your height(Meters):