实现复数类中的运算符重载（3）

#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+(int c1 ,Complex &c);
    friend Complex operator-(int c1 ,Complex &c);
    friend Complex operator*(int c1 ,Complex &c);
    friend Complex operator/(int c1 ,Complex &c);
    void display();
private:
    double real;
    double imag;
};
//下面定义成员函数
Complex operator+(int c1 ,Complex &c)
{
    return Complex(c1+c.real,c.imag);
}
Complex operator-(int c1 ,Complex &c)
{
     return Complex(c1-c.real,c.imag);
}
Complex operator*(int c1 ,Complex &c)
{
     return Complex(c1*c.real,c.imag);
}
Complex operator/(int c1 ,Complex &c)
{
     return Complex(c1/c.real,c.imag);
}
void Complex::display()
{
    cout<<"("<<real<<","<<imag<<"i"<<")"<<" ";
}
//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=5+c1;
    cout<<"5+c1=";
    c3.display();
    c3=5-c1;
    cout<<"5-c1=";
    c3.display();
    c3=3*c1;
    cout<<"3*c1=";
    c3.display();
    c3=3/c2;
    cout<<"3/c2=";
    c3.display();
    return 0;
}