What is Data abstraction:
-Data abstraction refers to providing only essential information to the outside world and hiding their background details.
-Data abstraction is a programming technique that relies on the separation of interface and implementation.
-In C++, classes provides great level of data abstraction. They provide sufficient public methods to the outside world to play with the functionality of the object and to manipulate object data, i.e., state without actually knowing how class has been implemented internally.