定义一个复数类Complex，重载运算符“+”，使之能用于复数的加法运算。参加运算的两个运算量可以都是类对象，也可以其中有一个是整数，顺序任意。例如，c1+c2,i+c1,c1+i均合法(设i为整数,c1,c2为复数)。编写程序，分别求两个复数之和、整数和复数之和。

两个复数
一个复数和一个整数
一个整数和一个复数

两个复数之和、复数和整数之和，整数和复数之和。

3 4 5 -10
3 4 5
5 3 4

c1+c2=(8.00,-6.00i)
c1+i=(8.00,4.00i)
i+c1=(8.00,4.00i)
#include <iostream>

#include <iomanip>

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+(int &i);

    friend Complex operator+(int&,Complex &);

    void display();

private:

    double real;

    double imag;

};

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

Complex Complex:: operator+(int &i)
{return Complex(real+i,imag);}
Complex operator+(int&i,Complex &c)
{return Complex(i+c.real,c.imag);}
void Complex::display()
{   cout<<"("<<real<<","<<imag<<"i)"<<endl;}




int main()

{

    double real,imag;

    cin>>real>>imag;

    Complex c1(real,imag);

    cin>>real>>imag;

    Complex c2(real,imag);

    cout<<setiosflags(ios::fixed);

    cout<<setprecision(2);

    Complex c3=c1+c2;

    cout<<"c1+c2=";

    c3.display();

    int i;

    cin>>real>>imag;

    cin>>i;

    c3=Complex(real,imag)+i;

    cout<<"c1+i=";

    c3.display();

    cin>>i;

    cin>>real>>imag;

    c1=Complex(real,imag);

    c3=i+c1;

    cout<<"i+c1=";

    c3.display();

    return 0;

}