This is done with the so-called dot notation wherein the object name followed by a dot followed by the function name is given. The Declaration File or the header file which declares what the class does . It identifies the variables and the functions of the class, and tells you how to use them. All of the information needed to use a class is declared in the Header File. The Implementation File which defines how the functions actually do their work .
Many different implementations are consistent with one given declaration.
The Header file has two sections labeled public and private . The functions and variables put into the public sections are availabe to all the user of the class. Those that are put into the private section are not available to the user. Usually you will wish to make the member functions public and the object variables private. Objects are generated from a class by use of a special member function called a constructor .