Base class pointer vs inherited class pointer?

Question

Suppose I have a class Dog that inherits from a class Animal. What is the difference between these two lines of code?

    Animal *a         


        

Answer 1

No, they aren't the same.

The Dog pointer is not as polymorphic as Animal. All it can point to at runtime is a Dog or a subclass of Dog. If there are no subclasses of Dog, then the Dog runtime type and compile time types are the same.

The Animal pointer can refer to any subclass of Animal: Dog, Cat, Wildebeast, etc.