slicing problem

 

 

代码

class Base{
public:
    Base():m(0){};
//Base(const Base& rhs):m(rhs.m){cout<<"Copy constructor, rhs is "<<&rhs<<" this pointer is "<<this<<endl;}
    void add(){m++;};
int m;
};
class Derived : public Base{};
int main(){
    Derived d;
    cout<<d.m<<endl;
    static_cast<Base&>(d).add();
    cout<<d.m<<endl;
//so called "slicing problem"
    static_cast<Base>(d).add();
 　 //Base(static_cast<Base&>(d)).add();
    cout<<d.m<<endl;
return 0;
}

 

嘿嘿，猜猜看static_cast<Base>(d).add(); 这一行，编译器到底干了些什么.