#include <iostream> #include <iomanip> using namespace std; class Time{ int hour, minute, second; public: Time(int h=0, int m=0, int s=0);//已实现 Time& operator++(); Time& operator--(); Time operator++(int); Time operator--(int); friend istream& operator>>(istream& in, Time& t);//已实现 friend ostream& operator<<(ostream& out, const Time& t);//已实现 };int main() { Time t; cin >> t; t++; cout << t << endl; --t; cout << t << endl; ++t; cout << t << endl; t--; cout << t << endl; return 0; } /* 请在这里填写答案，类设计及部分接口已有系统给出并实现，你只需要实现++和--运算符的重载 */

可以参考以下代码实现++和--运算符的重载：

#include <iostream>
#include <iomanip>
using namespace std;

class Time{
    int hour, minute, second;
public:
    Time(int h=0, int m=0, int s=0);
    Time& operator++(); // ++t
    Time& operator--(); // --t
    Time operator++(int); // t++
    Time operator--(int); // t--
    friend istream& operator>>(istream& in, Time& t);
    friend ostream& operator<<(ostream& out, const Time& t);
};

Time::Time(int h, int m, int s) {
    hour = h;
    minute = m;
    second = s;
}

Time& Time::operator++() {
    second++;
    if (second >= 60) {
        second = 0;
        minute++;
        if (minute >= 60) {
            minute = 0;
            hour++;
            if (hour >= 24) {
                hour = 0;
            }
        }
    }
    return *this;
}

Time& Time::operator--() {
    second--;
    if (second < 0) {
        second = 59;
        minute--;
        if (minute < 0) {
            minute = 59;
            hour--;
            if (hour < 0) {
                hour = 23;
            }
        }
    }
    return *this;
}

Time Time::operator++(int) {
    Time temp(*this);
    operator++();
    return temp;
}

Time Time::operator--(int) {
    Time temp(*this);
    operator--();
    return temp;
}

istream& operator>>(istream& in, Time& t) {
    in >> t.hour >> t.minute >> t.second;
    return in;
}

ostream& operator<<(ostream& out, const Time& t) {
    out << setfill('0') << setw(2) << t.hour << ":" << setw(2) << t.minute << ":" << setw(2) << t.second;
    return out;
}

int main() {
    Time t;

    cin >> t;
    t++;
    cout << t << endl;

    --t;
    cout << t << endl;

    ++t;
    cout << t << endl;

    t--;
    cout << t << endl;

    return 0;
}