8_2.cpp

来自「c++语言程序设计（第2版）》」· C++ 代码 · 共 65 行

#include<iostream.h>
class Clock	//时钟类声明
{
public:	//外部接口
	Clock(int NewH=0, int NewM=0, int NewS=0);
	void ShowTime();
	void operator ++();	//前置单目运算符重载
	void operator ++(int);	//后置单目运算符重载
private:	//私有数据成员
	int Hour,Minute,Second;
};
Clock::Clock(int NewH, int NewM, int NewS)	//构造函数
{
	if(0<=NewH&&NewH<24&&0<=NewM
		&&NewM<60&&0<=NewS&&NewS<60){
		Hour=NewH;
		Minute=NewM;
		Second=NewS;
	}
	else
		cout<<"Time error!"<<endl;
}
void Clock::ShowTime()	//显示时间函数
{
	cout<<Hour<<":"<<Minute<<":"<<Second<<endl;
}
void Clock::operator ++()	//前置单目运算符重载函数
{
	Second++;
	if(Second>=60){
		Second=Second-60;
		Minute++;
		if(Minute>=60){
			Minute=Minute-60;
			Hour++;
			Hour=Hour%24;
		}
	}
	cout<<"++Clock: ";
}
void Clock::operator ++(int)	//后置单目运算符重载
{		//注意形参表中的整型参数
	Second++;
	if(Second>=60){
		Second=Second-60;
		Minute++;
		if(Minute>=60){
			Minute=Minute-60;
			Hour++;
			Hour=Hour%24;
		}
	}
	cout<<"Clock++: ";
}
void main()
{
	Clock myClock(23,59,59);
	cout<<"First time output:";
	myClock.ShowTime();
	myClock++;
	myClock.ShowTime();
	++myClock;
	myClock.ShowTime();
}