第十二周项目1-实现复数类中的运算符重载（2）

*文件名称：test.cpp 

 *作   者：张明宇

 *完成日期：2016年5月15日 

 */

问题及代码：

请用类的友元函数，而不是成员函数，再次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;}
Complex operator+(const Complex &c2);
Complex operator-(const Complex &c2);
Complex operator*(const Complex &c2);
Complex operator/(const Complex &c2);
void display();
private:
double real;
double imag;
};
//下面定义成员函数
//复数相加： (a+bi)+(c+di)=(a+c)+(b+d)i.
Complex Complex::operator+(const Complex &c2)
{
Complex c;
c.real=real+c2.real;
c.imag=imag+c2.imag;
return c;
}
//复数相减：(a+bi)-(c+di)=(a-c)+(b-d)i.
Complex Complex::operator-(const Complex &c2)
{
Complex c;
c.real=real-c2.real;
c.imag=imag-c2.imag;
return c;
}
//复数相乘：(a+bi)(c+di)=(ac－bd)+(bc+ad)i.
Complex Complex::operator*(const Complex &c2)
{
Complex c;
c.real=real*c2.real-imag*c2.imag;
c.imag=imag*c2.real+real*c2.imag;
return c;
}

//复数相除：(a+bi)/(c+di)=(ac+bd)/(c^2+d^2) +(bc-ad)/(c^2+d^2)i
Complex Complex::operator/(const Complex &c2)
{
Complex c;
c.real=(real*c2.real+imag*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
c.imag=(imag*c2.real-real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
return c;
}

void Complex::display()
{
cout<<"("<<real<<","<<imag<<"i)"<<endl;
}
//下面定义用于测试的main()函数
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();
return 0;
}