C++ 运算符重载

C++ 运算符重载

概念：对已有的运算符进行定义，赋予其另一种功能，以适应不同的数据类型。

2种重载方式：

一、成员函数运算符重载
重载 + 号

class Persion
{
public:
	int m_A;
	int m_B;
	Persion operator+(Persion& p)
	{
		Persion temp;
		temp.m_A = this->m_A + p.m_A;
		temp.m_B = this->m_B + p.m_B;
		return temp;
	}
};

void test01()
{
	Persion p1;
	p1.m_A = 10;
	p1.m_B = 10;

	Persion p2;
	p2.m_A = 10;
	p2.m_B = 10;

	Persion p3 = p1 + p2; // 本质是：Persion p3 = p1.operator+(p2);
	cout << "p3.m_A = " << p3.m_A << " p3.m_B = " << p3.m_B << endl;
}

二、全局函数运算符重载

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

class Persion
{
	friend Persion operator+(Persion& p1, Persion& p2);
public:
	int m_A;
	int m_B;
};

Persion operator+(Persion& p1, Persion& p2)
{
	Persion temp;
	temp.m_A = p1.m_A + p2.m_A;
	temp.m_B = p1.m_B + p2.m_B;
	return temp;
}


int main()
{
	Persion p1;
	p1.m_A = 10;
	p1.m_B = 10;

	Persion p2;
	p2.m_A = 10;
	p2.m_B = 10;

	Persion p3 = p1 + p2;  // 本质是：Persion p3 = operator+(p1,p2);
	cout << "p3.m_A = " << p3.m_A << " p3.m_B = " << p3.m_B << endl;

	system("pause");
	return 0;
}

小知识：
运算符重载也可以发生函数重载

#include <iostream>
#include <string>

using namespace std;

class Persion
{
	friend Persion operator+(Persion& p1, Persion& p2);
public:
	int m_A;
	int m_B;
};

Persion operator+(Persion& p1, Persion& p2)
{
	Persion temp;
	temp.m_A = p1.m_A + p2.m_A;
	temp.m_B = p1.m_B + p2.m_B;
	return temp;
}

Persion operator+(Persion& p1, int num)
{
	Persion temp;
	temp.m_A = p1.m_A + num;
	temp.m_B = p1.m_B + num;
	return temp;
}

int main()
{
	Persion p1;
	p1.m_A = 10;
	p1.m_B = 10;

	Persion p2;
	p2.m_A = 10;
	p2.m_B = 10;

	Persion p3 = p1 + 10;  
	cout << "p3.m_A = " << p3.m_A << " p3.m_B = " << p3.m_B << endl;

	system("pause");
	return 0;
}