What is the advantage of using dynamic_cast instead of conventional polymorphism?

Question

We can use Polymorphism (inheritance + virtual functions) in order to generalize different types under a common base-type, and then refer to different objects as if they wer

Answer 1

It allows you to do things which you can only do to the derived type. But this is usually a hint that a redesign is in order.

struct Foo
{
  virtual ~Foo() {}
};

struct Bar : Foo
{
  void bar() const {}
};

int main()
{
  Foo * f = new Bar();
  Bar* b = dynamic_cast(f);
  if (b) b->bar(); 
  delete f;
}