第八周任务1：方案二：请用类的友元函数，而不是成员函数，完成上面提及的运算符的重载；

//2）方案二：请用类的友元函数，而不是成员函数，完成上面提及的运算符的重载；

#include <iostream>

using namespace std;

class Complex
{
public:
Complex(){real=0;imag=0;}
Complex(double r,double i){real=r;imag=i;}
friend Complex operator+(Complex &c1,Complex &c2);
friend Complex operator-(Complex &c1,Complex &c2);
friend Complex operator*(Complex &c1,Complex &c2);
friend Complex operator/(Complex &c1,Complex &c2);
void display();
private:
double real;
double imag;
};
//下面定义成员函数
Complex operator+(Complex &c1,Complex &c2)
{
Complex c ;
c.real=c1.real+c2.real;
c.imag=c1.imag+c2.imag;
return c ;
}
Complex  operator-(Complex &c1,Complex &c2)
{
Complex c ;
c.real=c1.real-c2.real;
c.imag=c1.imag-c2.imag;
return c ;
}

Complex operator*(Complex &c1,Complex &c2)
{
Complex c ;
c.real=c1.real*c2.real-c1.imag*c2.imag;
c.imag=c1.imag*c2.real+c1.real*c2.imag;
return c ;
}

Complex  operator/(Complex&c1,Complex &c2)
{
Complex c ;
c.real=(c1.real*c2.real+c1.imag*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
c.imag=(c1.imag*c2.real-c1.real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
return c ;
}
void Complex::display()
{
cout<<"("<<real<<","<<imag<<")"<<endl;
}

int main()
{
Complex c1(3,4),c2(5,-10),c3;
cout<<"c1=";
c1.display();
cout<<"c2=";
c2.display();
c3=c1+c2;
cout<<"c1+c2=";
c3.display();
c3=c1-c2;
cout<<"c1-c2=";
c3.display();
c3=c1*c2;
cout<<"c1*c2=";
c3.display();
c3=c1/c2;
cout<<"c1/c2=";
c3.display();
system("pause");
return 0;
}