注意：类内运算符重载时只能有且仅有一个参数；类内其他函数可以有多个参数。

如果参数过多：

方法一：利用全局函数类外实现；

方法二：利用友元类内实现

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

class person
{
public:
	person(int a, int b)
	{
		m_a = a;
		m_b = b;
	}
	int m_a;
	int m_b;

	person &add_person(person& p)
	{
		this->m_a+=p.m_a ;
		this->m_b += p.m_b;
		return *this;
	}

	person operator+(person& p) 
	{
		person temp(0,0);
		temp.m_a = this->m_a + p.m_a;
		temp.m_b = this->m_b + p.m_b;
		return temp;
	}

	//方法二：利用友元类内实现
	//friend ostream& operator<<(ostream& cout, person p);//本质：简化为cout<<p
	

};

//方法一：利用全局函数类外实现；
ostream& operator<<(ostream& cout, person p)//本质：简化为cout<<p
{
	cout << "m_a=" << p.m_a << "\tm_b=" << p.m_b;
	return cout;
}


int main()
{
	person p1(1, 2);
	person p2(1, 2);
	person p = p1 + p2;

	cout << p1<< endl;

	system("pause");
	return 0;
}