What is a node class

1. What is a node class? A node class is a class that,
   • relies on the base class for services and implementation,
   • provides a wider interface to the users than its base class,
   • relies primarily on virtual functions in its public interface
   • depends on all its direct and indirect base class
   • can be understood only in the context of the base class
   • can be used as base for further derivation
   • can be used to create objects.
   A node class is a class that has added new services or functionality beyond the services inherited from its base class.