Programming

See the following code:

Code:

#include<iostream>
using namespace std;
class Uncopyable
{
protected:
    Uncopyable(){cout<<"hehe\n";}
    ~Uncopyable(){}
private:
    Uncopyable(const Uncopyable &rhs){cout<<"oooops\n";};
    Uncopyable& operator=(const Uncopyable &rhs);
};

class Dog : private Uncopyable
{
    string name;
    int value;
public:

    Dog(const string &s, const int &v):name(s), value(v){}
public:
    //Dog(const Dog &rhs){};             //here is the question!
};

int main()
{
    Dog a("a", 9);
    Dog b(a);
}

If I comment out that line, g++ will complaint "Uncopyable::Uncopyable(const Uncopyable&) is private". I think that mean the default copy ctor of derived class created by g++ called the base class' copy ctor.


If I make available of that line, every thing is ok. It out put

Code:

hehe
hehe

I think this mean the default copy ctor of derived class created by g++ called the base class' default ctor.
Am I right? If yes, why doesn't the default copy ctor derived class, in condition 2, call the base class' copy ctor? Why it behave so inconsistently?

thank you!