运算符重载：复数类

运算符的重载：

1，只能重载已存在的运算符

2，自定义类型和内置满足的相同的逻辑

1.普通运算符可以重载

2.类型重载

const ：

1、防止实参被修改；

2、接收隐式生成临时对象；

类内是this_call的调用约定，成员方法隐藏this指针，指向一般为左操作数，所以只用传右操作数即可

代码如下：

class CComplex
{

public:

CComplex(int real, int img) :mreal(real), mimg(img){}  //构造

类内实现+的重载 右操作数类型为int

const CComplex operator+(int rhs)    
	{
		std::cout << "CComplex::operator+(int)" << std::endl;
		return CComplex(mreal + rhs, mimg);
	}

CComplex cc2 = cc1 + 10; //cc1.operator+(10);

//类内实现<<的重载

//std::ostream& operator<<(std::ostream& out)
	//{
	//	out << mreal << " ";
	//	out << mimg << " ";
	//	return out;
	//}

//cc1 << std::cout;左操作数是类内的对象

private:

int mreal;   //实部
int mimg;    //虚部

//类外不能访问类内的私有成员变量，设置友元函数

friend const CComplex operator+(int, const CComplex&);
	friend const CComplex operator+(const CComplex&, const CComplex&);
	friend std::ostream& operator <<(std::ostream&, const CComplex&);
};

类外是cd_call的调用约定,无this指针，需传两个对象

//类外实现+的重载 左操作数类型为int,右操作数类型为CComplex

const CComplex operator+(int lhs, const CComplex& rhs)
{
	std::cout << "global::operator+(int,CComplex)" << std::endl;
	return CComplex(lhs + rhs.mreal, rhs.mimg);
}

CComplex cc3 = 10 + cc2; //operator+(10,cc2);

//类外实现+的重载 左操右操作数类型都为CComplex

 const CComplex operator+(const CComplex& lhs, const CComplex& rhs)
    {
    	std::cout << "CComplex::operator+(CComplex, CComplex)" << std::endl;
    	return CComplex(lhs.mreal + rhs.mreal, lhs.mimg + rhs.mimg);
    }
CComplex cc4 = cc2 + cc3;

//类外实现<<的重载 左操作数为std::ostream的类型，右操作数为CComplex类型

std::ostream& operator <<(std::ostream& out, const CComplex& rhs)
{
	out << rhs.mreal << " ";
	out << rhs.mimg << " ";
	return out;
}

std::cout << cc1 << std::endl;