在复数类Complex内部实现运算符–和==

#include<iostream>
using namespace std;
class Complex
{
	int x,y;
public:
	Complex(int x1=0,int y1=0)
	{
		x=x1;
		y=y1;
	}
	Complex operator--(int)//后缀-- 
	{
		x--;
		y--;
		return Complex(x+1,y+1);	
	}
	Complex operator--()//前缀-- 
	{
		--x;
		--y;
		return Complex(x,y);
	}
	bool operator==(Complex &z1)
	{
		if(x==z1.x&&y==z1.y)
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	void print()
	{
		cout<<x;
		if(y>0)
		{
			cout<<"+"<<y<<"i"<<endl;
		}
		else
		{
			cout<<y<<"i"<<endl;
		}
	}
};
int main()
{
Complex c1(5,6);
Complex c2(10,11);
Complex c3(20,21);
Complex c4;
Complex c5;
Complex c6(2,3);
c4=c1--;
c5=(--c2);
c4.print();
c5.print();
cout<<"c6==c3 is "<<(c6==c3)<<endl;
return 0;
}