C++重载——单目运算符重载（时钟类）

本题已给出时钟类及其成员函数实现，要求补充完整运算符++重载函数（前置和后置），使之能够实现时钟对象自增1秒。

时钟类定义如下。

class Clock {
	public:
		Clock(int NewH=0, int NewM=0, int NewS=0);
		void ShowTime();
		friend Clock operator++(Clock& op);         //前置单目运算符重载
		friend Clock operator++(Clock& op,int);     //后置单目运算符重载
	private:
		int Hour, Minute, Second;
};

裁判测试程序样例：

#include<iostream>
using namespace std;

class Clock {
	public:
		Clock(int NewH=0, int NewM=0, int NewS=0);
		void ShowTime();
		friend Clock operator++(Clock& op);         //前置单目运算符重载
		friend Clock operator++(Clock& op,int);     //后置单目运算符重载
	private:
		int Hour, Minute, Second;
};

Clock::Clock(int NewH, int NewM, int NewS) {
	Hour=NewH;
	Minute=NewM;
	Second=NewS;
}
void Clock::ShowTime() {
	cout<<Hour<<":"<<Minute<<":"<<Second<<endl;
}

/*---------请在这里填写答案-----------*/

int main() {
	int h, m, s;
	cin>>h>>m>>s;
	Clock a(h,m,s);

	(++a).ShowTime();
	(a++).ShowTime();
	a.ShowTime();

	return 0;
}

运算符重载函数的定义。

Clock operator++(Clock& op) {
	op.Second++;
	if (op.Second == 60) {
		op.Second = 0;
		op.Minute++;
	}
	if (op.Minute == 60) {
		op.Minute = 0;
		op.Hour++;
	}
	if (op.Hour == 24) {
		op.Hour = 0;
	}
	return op;
}
Clock operator++(Clock& op, int) {
	Clock t = op;
	op.Second++;
	if (op.Second == 60) {
		op.Second = 0;
		op.Minute++;
	}
	if (op.Minute == 60) {
		op.Minute = 0;
		op.Hour++;
	}
	if (op.Hour == 24) {
		op.Hour = 0;
	}
	return t;
}