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Stephen Pan
Stephen Pan

Reputation: 9

Why does my C program do not jump out the while loop even when the exit condition is met

#include<stdio.h>
#include <limits.h>

int main()
{
    int value;
    int smallest = INT_MAX;

    printf("This is a program that finds out the minimum \nof serveral integers you entered.");
    printf("Please type in these integers: ");

    while(scanf("%d", &value) != EOF)
    {
        printf(" ");

        if(value <= smallest)
        {
            smallest = value;
            printf("%d", smallest);    // to trace the while loop
        }
    }
    printf("\nThe smallest integer is: %d", smallest);    // this will execute once the program is stopped
    return 0;
}

This code can find the smallest integer successfully, but just doesn't print the result from 

printf("\nThe smallest integer is: %d", smallest);

.. until I stop the program from my C intepreter. I don't understand why it does not print immediately, since there are no more iterations in the while loop.

Upvotes: 0

Views: 109

Answers (2)

vinaykp
vinaykp

Reputation: 549

You can't use EOF like that , because scanf() returns value 1 after a successful read.scanf() wont return the character it read. I have given solution below, I think it works as you wanted.For any queries comment below.

#include<stdio.h>
#include <limits.h>

int main()
{
    int value;
    int smallest = INT_MAX;

    printf("This is a program that finds out the minimum \nof serveral integers you entered.");
    printf("Please type in these integers (Enter any other character to terminate): ");
    while(scanf("%d", &value))
    {


        if(value <= smallest)
        {
            smallest = value;
            printf("smallest till now: %d\n", smallest);    // to trace the while loop
        }
        else
            printf("smallest till now: %d\n", smallest);    // to trace the while loop

     }  
     printf("\nThe smallest integer is: %d\n", smallest);    // this will execute once the program is stopped
     return 0;
}

Upvotes: 1

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53006

The better end loop condition, is

while (scanf("%d", &value) == 1)

which means while scanf() is reading values succesfuly.

Read the link to understand why, when using scanf() it's not natural to wait for EOF because then the user would have to press a key combination to mark stdin with EOF.

That key combination is actually so akward that it's not the same for linux terminals Ctrl+D and for Windows cmd windows Ctrl+Z.

If it does not execute the printf() statement, it's because you need to flush the stdout, either add fflush(stdout) or add a '\n' at the end of every line, it's more natural to add a newline at the end, although I see that many people add it at the beinning.

Upvotes: 4

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