Inheritance Hierarchies
	• Every hierarchy has a root (e.g., base class) which has zero or more children. • Each child (e.g., derived class) is either a leaf or branches into children of its own. • Each class is inherently related to its parent, as well as to its ancestors. • In C++, the root of each hierarchy or sub-hierarchy is called a base class. • If the base class is the parent of the class in question, then it is a direct base class. Otherwise, if it is an ancestor, then it is an indirect base class.