C++重载操作符+, - , *, <<的方法

C++操作符重载的简单例子

重载操作符+, - , *, <<的方法

#include "stdafx.h"
#include <iostream> 

using namespace std;

class Time
{
private:
	int hours;
	int minutes;

public:
	Time();
	Time(int h, int m = 0);
	Time operator+(const Time &t) const;
	Time operator-(const Time &t) const;
	Time operator*(double n) const;
	friend ostream & operator<<(ostream &os, const Time &t);
};

Time::Time()
{
	hours = 0;
	minutes = 0;
}

Time::Time(int h, int m)
{
	hours = h;
	minutes = m;
}

Time Time::operator +(const Time &t) const
{
	Time sum;
	sum.minutes = minutes + t.minutes;
	sum.hours = hours + t.hours + sum.minutes / 60;
	sum.minutes %= 60;
	return sum;
}

Time Time::operator -(const Time &t) const
{
	Time diff;
	int tot1, tot2;
	tot1 = t.minutes + t.hours * 60;
	tot2 = minutes + hours * 60;
	diff.minutes = (tot2 - tot1) % 60;
	diff.hours = (tot2 - tot1) / 60;
	return diff;
}

Time Time::operator *(double n) const
{
	Time result;
	long totalminutes = hours * n * 60 + minutes * n;
	result.hours = totalminutes / 60;
	result.minutes = totalminutes % 60;
	return result;
}

ostream & operator<<(ostream &os, const Time &t)
{
	os<<t.hours<<"hours, "<<t.minutes<<"minutes.";
	return os;
}

int main() 
{ 
	Time t1(8, 20);
	Time t2(20, 45);

	cout<<"t1 = "<<t1<<endl;
	cout<<"t2 = "<<t2<<endl;
	cout<<"t1 + t2 = "<<t1 + t2<<endl;
	cout<<"t2 - t1 = "<<t2 - t1<<endl;
	cout<<"t1 * 2 = "<<t1 * 2<<endl;

	system("pause");
	return 0; 
}