Programs are composed of a set of modules called classes. Each class is a template |
specifying a set of behaviors on |
the data of the class. |
Each class has class variables |
(sometimes called instance vars) |
to hold the data and methods (called |
functions or procedures in other |
languages) to define the behaviors. |
Each object in a program is created |
as an instance of a class. Each class |
instance has its own copy of the class |
variables. |
Classes can be used for data encapsulation, hiding the details of the data representation from the user of the class (by marking variables as private). |