有如下程序:
#include <iostream>
using namespace std;
class Complex
double re,im;
public:
Complex(double r, double i):re(r), im(i)
double real() const return re;
double image() const return im;
Complex& operator+=(Complex a)
re+=a.re;
im+=a.im;
return *this;
;
ostream& operator<<(ostream& s,const Complex& z)
return s<<'('<<z.real()<<','<<z.image()<<')';
int main()
Complex x(1,-2),y(2,3);
cout<<(x+=y)<<endl;
return 0;
执行这个程序的输出结果是( )。
A.(1,-2)
B.(2,3)
C.(3,5)
D.(3,1)