How many vtable and vpointers will be created in this example? [closed]

Question

Here is the program on vtables. Am I understanding is correct on vtables and v-pointers.

Class B
{
  public:

  virtual Void Hello()
  {
    cout<<"Hello Base";
  }
};

class D: public B    
{
  public:

  virtual void Hello()
  {
    cout<<"Hello Derived";
  }
};

int main(int argc, char* argv[])
{
  D *d1 = new D();
  D *d2 = new D();
  D *d3 = new D();

  return 0;
}

In my opinion, there will be two vtables and only one vptr. Am I correct on it?

Answer 1

The standard does not define how virtual functions are actually implemented, only how they should behave. So what you are asking for entirely depends on the compiler you are using.

---

GCC will in theory most likely create two vtables (one for B and one for D) and three vptrs (one for each of the object instances d1, d2, d3).

Have a look here: http://en.wikipedia.org/wiki/Virtual_method_table