Another feature of the object-oriented programming is the data encapsulation, that enable the control of how the user access the classes’ variables. If we declare any variable or function as public, it will be accessible inside and outside the class, i.e., not only the functions inside the class will be able to use it but also any function in any part of the program. Otherwise, if they are declared private, it is only possible to access it from inside the class, that is, only functions that are declared in the class can make a direct access to such variables. So, in the project of a class, it is possible to select what the user will be able to directly access and what is private information to the class.