Class implementation file
In object-oriented programming, a class implementation file is often used to contain the implementation code for the method(s) of a class. Using this structure, a class definition file containing the declaration of the class and its members is also created. If the class definition has been included and the implementation file for its methods is available, the user can instantiate an object of the class. The purpose of this structure is to keep the implementation code hidden, but allow the user to view the design. This allows the user the information needed to use the class effectively, but prevent him or her from damaging the compiled code.