自己解
大案在下面
#include <iostream>
using namespace std;
int main()
{
int h1, m1, h2, m2;
while (cin >> h1 >> m1 >> h2 >> m2)
{
if (h1 == 0 && m1 == 0 && h2 == 0 && m2 == 0)
{
break;
}
int ans = h2 * 60 + m2 - h1 * 60 - m1;
if (ans < 0)
{
ans += 1440;
}
cout << ans << endl;
}
}