Someone gave me a big doubt about virtual functions. Can some one remind me which is the correct way about this:


Code:
class Base
{
  ...
  virtual void display() = 0;
  ...
};

class Derived : public Base
{
  ...
  virtual void display();
  ...
};
Must we put the keyword "virtual" before the function display in Derived, or must we not put it, or can we do what we want.