用友元函数重载加号,进行复数和实数的加法时加号两端的操作数怎么还是不能互换?以下面程序为例：
#include
using std::cout;
using std::endl;
class Complex
{
friend Complex operator +(double d,const Complex &c);
public:
Complex(){dReal=0;dImag=0;}
Complex(double r,double i){dReal=r; dImag=i;}
void print()const;
private:
double dReal;
double dImag;
};
//友元函数实现
Complex operator +(double d,const Complex &c)
{
return Complex(d+c.dReal,c.dImag);
}
void Complex::print()const
{
cout