第二題

#include <iostream>
using namespace std;
class Complex
 {public:
   Complex(){real=0;imag=0;}
   Complex(double r,double i){real=r;imag=i;}
   Complex operator+(Complex &c2);
   Complex operator-(Complex &c2);
   Complex operator*(Complex &c2);
   Complex operator/(Complex &c2);
   void display();
  private:
   double real;
   double imag;
 };


Complex Complex::operator+(Complex &c2)
{Complex c;
 c.real=real+c2.real;
 c.imag=imag+c2.imag;
 return c;}


Complex Complex::operator-(Complex &c2)
{Complex c;
 c.real=real-c2.real;
 c.imag=imag-c2.imag;
 return c;}


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


Complex Complex::operator/(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;}


int main()
{Complex c1(3,4),c2(5,-10),c3;
 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;
}