Data abstraction and encapsulation.

Data abstraction and encapsulation.

The wrapping up of data and functions into a single unit is called as encapsulation.
Data encapsulation is the most striking feature of class.
The data is not accessible to the outside world, and only those functions which are wrapped in a class can access it.
These functions provide an interface between object data and programmer.
This insulation of data from direct access by the program is called Data hiding or information hiding.


Abstraction 

refers to the act of representing essential features without including the background details or explanation .
Classes use the concepts of abstraction and are defined as list of abstract attribute such as size,weight and cost, the functions to operate on these attributes.
They encapsulate essential properties of objects that are to be created.
The attributes are some time called Data members because they hold information.
The functions that operates on these data are called member functions.