有以下程序: #include<iostream> using namespace std; class Complex { public: Complex(dOuble r=0,dOuble i=0):re(r),im(i){} doublereal()const{return re;} doubleimag()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’<<endl; return 0; } 程序执行后的输出结果是( )。
A.6+6i
B.6+1i
C.1+6i
D.1+1i