I was recently on an interview for a position where C/C++ is the primary language and during one question I was told that it's possible to use the vtable to determine which class in a hierarchy a base pointer actually stores.

So if, for example you have

    class A  
    {  
    public:  
    A() {}  
    virtual ~A() {}  
    virtual void method1() {}  
    };

    class B : public A  
    {  
    public:  
    B() {}  
    virtual ~B() {}  
    virtual void method1() {}  
    };

and you instantiate A * pFoo = new B(), is it indeed possible to use the vtable to determine whether pFoo contains a pointer to an instance of A or B?