#include <iostream>

using namespace std;

class complex

{

public:

complex (double r= 0, double i = 0)

:re (r) , im(i)

{ }

complex operator += (const complex& c)

{

this->re = c.re + this->re;

this->im = c.im + this->im;

return * this;

}

double real () const {return re;}

double imag () const {return im;}

private:

double re,im;

friend complex&_dopal (complex*,const complex&);

};

ostream & operator<< (ostream & os, const complex& x)

{

return os<< '(' << x.real () <<','

<< x.imag () <<'(';

}

//尽量不要 pass by value 引用就是一个指针

int main()

{

complex c(1,2), d(2,3),e(1,1),a(5,5);

a += c += d;

cout << a;

return 0;

}