시간 차 구하기

#include<iostream>
#include<algorithm>


using namespace std;

int main() {
	char *temp=NULL;
	int h = 0, m = 0, s = 0;
	char time1[100], time2[100];
	int gap = 0, t1 = 0, t2 = 0, rh = 0, rm = 0, rs = 0;
	char ch[10], cm[10], cs[10];


	cin.getline(time1, 100);

	strtok_s(time1, " ",&temp);
	h = atoi(strtok_s(temp, ":", &temp));
	m = atoi(strtok_s(temp, ":", &temp));
	s = atoi(strtok_s(temp, ":", &temp));

	t1 = h * 3600 + m * 60 + s;

	cin.getline(time2, 100);
	strtok_s(time2, " ", &temp);
	h = atoi(strtok_s(temp, ":", &temp));
	m = atoi(strtok_s(temp, ":", &temp));
	s = atoi(strtok_s(temp, ":", &temp));

	t2 = h * 3600 + m * 60 + s;

	gap = t2 - t1;

	if (time1[0] != time2[0]) {
		gap += 12 * 3600;
	}

	rh = gap/3600;
	gap -= rh * 3600;
	rm = gap/60;
	gap -= rm * 60;
	rs = gap;

	if (rh < 10) 
		sprintf_s(ch, sizeof(ch), "0%d", rh);
	else
		sprintf_s(ch, sizeof(ch), "%d", rh);

	if (rm < 10)
		sprintf_s(cm, sizeof(cm), "0%d", rm);
	else
		sprintf_s(cm, sizeof(cm), "%d", rm);

	if (rs < 10)
		sprintf_s(cs, sizeof(cs), "0%d", rs);
	else
		sprintf_s(cs, sizeof(cs), "%d", rs);


	cout << ch<<":" << cm << ":" << cs;
	return 0;
}