What is polymorphism, what is it for, and how is it used?

Question

What is polymorphism, what is it for, and how is it used?

Answer 1

Polymorphism is the ability to treat a class of object as if it is the parent class.

For instance, suppose there is a class called Animal, and a class called Dog that inherits from Animal. Polymorphism is the ability to treat any Dog object as an Animal object like so:

Dog* dog = new Dog;
Animal* animal = dog;