Objects And Inheritance

Classes vs. Objects

An object is an organization of methods and data during runtime, treated as a single entity.

A class is a piece of code that describes how an object is organized.

A class may generate hundreds of objects or none at all.  However, an object has exactly one class that defines it.

If class A inherits from Class B.  (We call class B the base class.  We call class A the inherited class.)

Colloquially, we think an A object as being a special kind of B object.  An A object is of class A...but it is also of class B.  A B pointer is allowed to point to an A object.  (But not the other way around.)

Imagine Dog inherits from Animal.  This means all Dogs are also Animals.  Animal pointers can point to Dogs...but they are still Dogs.