Chapter 3 summary Chapter 3 summary Class hierarchies are used to construct a complex object in a number of simpler stages.
Class hierarchies make construction, debugging and maintenance easier and encourage reuse.
Every class in a hierarchy has only one parent class, but a class can have any number of child classes. A child class is an extension of its parent and inherits all of its parent's resources. Abstract classes are only used as the foundation of non-abstract classes. All the classes in a hierarchy should be collected together in a package of classes. Classes have public, private and protected resources.