C++运算符重载

#include<iostream>
using  namespace std;
class complex{
     double real,imag;
     public:
    complex( double r= 0, double i= 0){
        real=r;
        imag=i;
    }
    complex  operator+ (complex &c2);
     void display();
};
complex complex:: operator+(complex &c2)
{
    complex c;
    c.real=real+c2.real;
    c.imag=imag+c2.imag;
     return c;
}
void complex::display(){
    cout<<real<< " + "<<imag<< " i "<<endl;
}
int main()
{
    complex a( 1, 2),b( 2, 3),c;
    c=a+b;
    c.display();
}

还有种更简单的方法，重载函数还可以这样写

complex complex::operator+(complex &c2)

{
    return complex(real+c2.real,imag+c2.imag);
}