Definition of OOP:

OOP uses objects as its fundamental building blocks. Each object is an instance of some class. Classes allow the mechanism of data abstraction for creating new data types. Inheritance allows building of new classes from existing classes. Hence if any of these elements are missing in a program we cannot consider that program as objected oriented program. Object-oriented programming is a programming methodology that associates data structures with a set of operators which act upon it. In OOP’s terminology an instance of such an entity is known as an object. It gives importance to relationships between objects rather than implementation details. Hiding the implementation details within an object results in the user being more concerned with an objects relationship to the rest of the system, than the implementation of the object’s behavior.