Infinite loop in C

Question

The program should accept input values on stdin until EOF is reached. The input is guaranteed to be well-formed and contain at least one valid floating point value.

Sample input:

Expected output:

3 3 4

 7 7 8

 -16 -16 -15

 Done.

#include <stdio.h>  

#include <math.h>  

#include <stdlib.h>  



int main(void) 

{  

    for(;;)  

    {  

        float b;          

        scanf("%f", &b);  

        printf("%g %g %g\n",floor(b), round(b), ceil(b));  

        int i=0;  

        int result = scanf("%d", &i);  



        if( result == EOF)  

        {  

            printf("Done.\n");  

            exit(0);  

        }  



     }  

    return 0;  

}

My program only runs one time. After that it outputs

0 1 1

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Answer 1

If you want to stay with the scanf, you can use the return value to detect a erroneous/EOF input:

#include <stdio.h>  
#include <math.h>  
#include <stdlib.h>  

int main(void) 
{  
    int result = 0;
    for(;;)  
    {  
        float b;
        result = scanf(" %f", &b); 
        if(result == EOF)
            break;

        printf("%g %g %g\n",floor(b), round(b), ceil(b));  
     }  
     printf("Done");
    return 0;  
}

Try it here.

Also a look at this question is helpful.

Infinite loop in C

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