C++ 一元运算符的重载（前置++ --，后置 ++ --）

#include<iostream>
using namespace std;

class Complex
{
public:
	friend Complex& operator++(Complex &tmp);
	friend Complex operator++(Complex &tmp, int);
	Complex(int a=0, int b=0)
	{
		this->a = a;
		this->b = b;
	}
	//成员函数实现 前置--
	Complex operator--()
	{
		this->a--;
		this->b--;
		cout << "a="<<a  <<"  b="<<b<< endl;
		return *this;
	}
	Complex& operator--(int)
	{
		Complex tmp = *this;
		this->a--;
		this->b--;
		return tmp;
	}
	void printfm()
	{
		cout << this->a<< endl;
		cout <<this->b << endl;
	}
private:
	int a;
	int b;

};
//全局函数实现前置++
Complex& operator++(Complex &tmp)
{
	tmp.a++;
	tmp.b++;
	cout <<"a="<<tmp.a <<"   b="<<tmp.b<< endl;
	return tmp;
}
//全局函数实现后置++
Complex operator++(Complex &tmp,int)
{
	Complex c = tmp;
	tmp.a++;
	tmp.b++;
	return c;
}
void main()
{
	Complex c1(1, 1);
	Complex c2(2, 2);
	//全局函数实现前置++
	Complex c3=operator++(c1);

	//成员函数实现前置--
	Complex c4(5,5);
	c4.operator--();

	//全局函数实现后置++
	Complex c5(7, 7);
	//c5.printfm();     
	Complex c6=c5++;
	c6.printfm();//输出为 7 ，7

	//成员函数实现后置--
	Complex c7(9, 9);
	Complex c8=c7--;
	c8.printfm();
	c7.printfm();
	system("pause");
}