Why do we need virtual table?

Question

I was looking for some information about virtual table, but can\'t find anything that is easy to understand.
Can somebody give me good examples(not from Wiki, please) wi

Answer 1

To answer your headline question - you don't, and the C++ Standard does not specify that you must be provided with one. What you do want is to be able to say:

struct A {
  virtual ~A() {}
  virtual void f() {}
};

struct B : public A {
  void f() {}
};

A * p = new B;
p->f();

and have B::f called and not A::f. A virtual function table is one way of implementing this, but is frankly not of interest to the average C++ programmer - I only ever think about it when answering questions like this.