c++ - 计算C++的军事时间时差

我必须编写一个程序，以军事时间格式给出两次之间的差值。例如，

请输入第一次:1730
请输入第二次:0900
输出= 15小时30分钟

这是我想出的程序(*不允许在if语句，循环或函数中使用)

我只需要知道这是对还是错？

int main()
{

    int first;
    int second;

    cout << "Please enter the first time:";
    cin >> first;
    cout << endl;

    cout << "Please enter the second time:";
    cin >> second;
    cout << endl;

    int am = first - 1200;
    second = second + 1200;

    int amhour = am/100;
    int ammins = am%100;

    int hours = second - amhour*100;

    int real_hr = hours - 40;
    int final_time = real_hr - ammins;
    int final_hours = final_time/100;
    int final_mins = final_time%100;

    cout << final_hours << " hours and " << final_mins << " minutes." << endl;

    return 0;
}

最佳答案

我首先将每次转换为“自午夜以来的分钟数”，然后从第二个中减去第一个，然后使用它来形成输出。
但是，您可能需要考虑到，例如，如果第一次是2330而第二次是0030(跨越日期边界)，则减法会给您带来负数。
您可以通过简单地将1440分钟(一天)添加到该差异中，然后使用取模运算符来减少这一天(如果超过一天)来解决此问题。
因此，我将从以下内容开始:

#include <iostream>

int main() {
    // Get times from user.

    int first, second;
    std::cout << "Please enter the first time:  "; std::cin >> first;
    std::cout << "Please enter the second time: "; std::cin >> second;

    // Convert both to minutes since midnight.

    first = (first / 100) * 60 + first % 100;
    second = (second / 100) * 60 + second % 100;

    // Work out time difference in minutes, taking into
    // account possibility that second time may be earlier.
    // In that case, it's treated as the following day.

    const int MINS_PER_DAY = 1440;
    int minutes = (second + MINS_PER_DAY - first) % MINS_PER_DAY;

    // Turn minutes into hours and residual minutes, then output.

    int hours = minutes / 60;
    minutes = minutes % 60;
    std::cout << hours << " hours and " << minutes << " minutes.\n";
}