Question

I have seen this question http://www.careercup.com/question?id=384062

class Base {
public :
    virtual void method () = 0;
private :
    int n;
};

void Base::method() { n = 1;}

class D1 : Base {};

class D2 : public D1 {
    int i;
    void method() {i = 2;}
};

It passed the compiler of vs2008 and g++ 4.4.3

Here is my understanding of above code, please correct me if I am wrong

S1> D1 has inherited variable Base::n but it cannot access it.

S2> D1 has inherited the function Base::method but it doesn’t call/modify this inherited function in the above implementation.

S3> D2::method is not an overridden version of D1::method

Answer 1

D1 has inherited variable Base::n but it cannot access it.
Correct.
Private members of a class are never accessible from anywhere except the members of the same class.

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D1 has inherited the function Base::method but it doesn’t call/modify this inherited function in the above implementation.
Correct, but conditonally, Read below for why:

D1 inherits the Base::method but it is not calling/invoking it because you did’nt add any statement to do so. But it can call it.
Pure virtual functions can have a body and they can be called by drived class members just like any other member function.

class D1 : Base 
{
    public:
        void doSomething()
        {
            Base::method();
        }

}; 

Note that in your Base class n is private so the only way to access it is through member function of Base & since only method() can do so, You can do it through it.

Note that presence of atleast one pure virtual function makes an class Abstract Class, And one cannot create objects of an Abstract class. Any class deriving from an Abstract class must override ALL the pure virtual functions of the Base class or else the derived class becomes an Abstract class as well.

Based on above rule,
In your case both Base and D1 are Abstract classes.

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D2::method is not an overridden version of D1::method
Incorrect
Though method() is not acessible to the ouside world through instance of class D1, it is still very much a part of it. Access control dictates access rights not presence or absence of members.
So, Yes, D2::method is an overriden version of D1::method and it hides it as well, just that in this case, D1::method was not acccessible in the first place