INHERITANCE AND SUBCLASSES?
Inheritance is a useful feature found in nearly all object
oriented programming languages. Suppose a programmer finds a class which
does 90% of what they are looking for. It would be nice to be able to
customize this class without first creating a copy of it.
Inheritance allows a programmer to customize or extend the capabilities
of a particular class without duplicating all of the methods of the original
A class which extends the capabilities of another class is referred to
as a subclass. Subclasses silently inherit most of the
capabilities of the parent. Thus the programmer need only write the new
methods unique to the subclass.