View Code of Problem 56

#include<bits/stdc++.h>
using namespace std;
int main(){
	int h1,h2,m1,m2,s1,s2;
	int M1,M2,t;
	scanf("%d:%d:%d",&h1,&m1,&s1);
	scanf("%d:%d:%d",&h2,&m2,&s2);
	M1 = s1 + m1*60 + h1 * 60*60;
	M2 = s2 + m2*60 + h2 * 60*60;
	if(M1 > M2){
		t = h1;
		h1 = h2;
		h2 = t;
		
		t = m1;
		m1 = m2;
		m2 = t;
		
		t = s1;
		s1 = s2;
		s2 = t;
	}
	int ds = 0;	
	while(h2 > h1|| m2 > m1 || s2 > s1){
		s1++;
		if(s1==60){
			m1++;
			s1 = 0;
		}
		if(m1==60){
			h1++;
			m1 = 0;
		}
		ds++;	
	}
	int a,b,c;
	a = ds /3600;
	b = (ds - 3600*a)/60;
	c = ds - 3600*a - 60*b;
	printf("%d:%02d:%02d",a,b,c);
	return 0;
}