C++编写一个时间类 实现时间的加减运算并输出 同时实现正数计时和倒数计时

C++编写一个时间类 实现时间的加减运算并输出 同时实现正数计时和倒数计时

#include<iostream>
#include<windows.h>
using namespace std;

class Time {
public:
    int minute;
    int sec;
    Time() {                            //默认构造函数
        minute = 0;
        sec = 0;
    }
    Time(int m, int s):minute(m), sec(s)//构造函数重载
    {}                                    
    Time& operator++();                    //声明运算符“++”重载为成员函数
    Time& operator--();                    //声明运算符“--”重载为成员函数
    friend Time& operator+=(Time& a, Time& b);
    //声明运算符“+=”重载为友元函数
    friend Time& operator-=(Time& a, Time& b);                    
    //声明运算符“-=”重载为友元函数
    void Print();
};
Time& Time::operator++() {                //重载“++”运算符
    sec++;
    if (sec >= 60) {
        sec -= 60;
        minute++;
    }
    return *this;
}
Time& Time::operator--() {                //重载“--”运算符
    sec--;
    if (sec < 0) {
        sec += 60;
        minute--;
    }
    return *this;
}
Time& operator+=(Time& a, Time& b) {    //重载“+=”运算符
    int minute;
    int sec;
    if (a.sec + b.sec >= 60) {
        a.sec += b.sec;
        a.sec -= 60;
        a.minute++;
    }
    else {
        a.sec += b.sec;
    }
    if (a.minute + b.minute >= 60) {
        a.minute += b.minute;
        a.minute -= 60;
    }
    else {
        a.minute += b.minute;
    }
    return a;
}
    
Time& operator-=(Time& a, Time& b) {    //重载“-=”运算符
    int minute;
    int sec;
    int t1, t2, t;
    t1 = a.minute * 60 + a.sec;
    t2 = b.minute * 60 + b.sec;
    if (t1 >= t2) {
        t = t1 - t2;
    }
    else {
        t = t2 - t1;
    }
    a.minute = t / 60;
    a.sec = t % 60;
    return a;
}

void Time::Print() {                    //显示成员函数
    cout << "当前时间是：";
    cout << minute << "分" << sec << "秒" << endl;
}

int main() {
    Time time1, time2, time3;
    int a;
    cout << "请输入分钟：" << endl;
    cin >> time1.minute;
    cout << "请输入秒钟：" << endl;
    cin >> time1.sec;
    cout << "当前时间是：" << time1.minute << "分:" << time1.sec << "秒" << endl;
    cout << "--------------------------------" << endl;
    cout << "请输入操作" << endl << "1.整数计时" << endl << "2.倒数计时" << endl << "3.时间相加" << endl << "4.时间相减" << endl;
    cout << "--------------------------------" << endl;
    while (scanf("%d", &a) != EOF) {
        switch (a) {
        case 1:
            for (int i = 0; i < 8; i++) {
                ++time1;
                Sleep(1000);
                time1.Print();
            }
            break;
        case 2:
            for (int i = 0; i < 8; i++) {
                --time1;
                Sleep(1000);
                time1.Print();
            }
            break;
        case 3:
            cout << "请输入需要相加的时间（分钟）" << endl;
            cin >> time2.minute;
            cout << "请输入需要相加的时间（秒钟）" << endl;
            cin >> time2.sec;
            time1 += time2;
            time1.Print();
            break;
        case 4:
            cout << "请输入需要相减的时间（分钟）" << endl;
            cin >> time3.minute;
            cout << "请输入需要相减的时间（秒钟）" << endl;
            cin >> time3.sec;
            time1 -= time3;
            time1.Print();
            break;
        }
    }
    return 0;
}