有以下程序
#include ＜iostream＞
using namespace std;
class Complexpublic:
Complex(double r=0,double i=0):re(r),im(i)
double real() const return re;
double imag() const return im;
Complex operator+(Complex c) const
return Complex(re+c.re,im+c.im);
private:
double re,im;
;
int main() Complex a =Complex(1,1)+ Complex(5);
cout＜＜

A．real()＜＜’+’＜＜a.imag()＜＜’i’＜＜end1;
retura 0;
A. 6+6iB. 6+1iC. 1+6iD. 1+1i