View Code of Problem 56

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

char a[105], b;

int main()
{
    int h1, m1, s1, h2, m2, s2;
    while (scanf("%d:%d:%d", &h1, &m1, &s1) != EOF) {
        scanf("%d:%d:%d", &h2, &m2, &s2);
        int k1 = h1 * 3600 + m1 * 60 + s1;
        int k2 = h2 * 3600 + m2 * 60 + s2;
        
        if (k1 <= k2) {
            int p = k2 - k1;
            int h = p / 3600;
            int m = (p - h * 3600) / 60;
            int s = (p - h * 3600 - m * 60);
            printf("%d:%02d:%02d\n", h, m, s);
        }
        else {
            int p = - (k2 - k1);
            int h = p / 3600;
            int m = (p - h * 3600) / 60;
            int s = (p - h * 3600 - m * 60);
            printf("%d:%02d:%02d\n", h, m, s);
        }
    }
}