What Is Basic Concepts Of Object-Oriented Programming?

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1.Object and Class:-
  • Objects are the basic runtime entities in an object-oriented system.
  • They may represent a person,a place,a bank account , a table of data or any item that the program may handle.
  • They may also represent user-defined data such  as vectors and lists.
  • Any programming is analyzed in terms of objects and the nature of communication between them.
  • Program objects should be chosen such that they match closely with the real world objects.
  • As pointed out earlier , an object takes up space in the memory and has an associated address like a record in Pascal, or a structure in C.
  • When a program is executed the objects interact by sending message to one another.
2.Data Abstraction and Encapsulation:-
  • The wrapping up of data and methods into a single unit(called class) is known as encapsulation.
  • Data encapsulation is the most striking feature of a class.
  • The data is not accessible to the outside world and only those methods,which are wrapped in the class, can access it.
  • These methods provide the interface between the object's data and the program.
  • This insulation of the data from direct access by the program is called data hiding.
  • Encapsulation makes it possible for objects to be treated like 'black boxes', each performing a specific task without any concern for internal implementation.
  • Abstraction refers to the act of representing essential features without including the background details or explanations.
  • Classes use the concept of abstraction and are defined as a list of abstract attributes such as size , weight and cost, and methods that operate on these attributes.
  • They encapsulate all the essential properties of the objects that are to be created.
  • Encapsulation is one of the three OOP  principle. 
 3.Inheritance 
  • Inheritance is the process by which objects of one class acquire the properties of objects of another class.
  • Inheritance  support the concept oh hierarchical classification .
  • For example, the bird robin is a part of the class flying bird,which is again a part of the class bird.
  • In java , the derived class is known as 'subclass'.
  • Note that each subclass defines only those feature that are unique to it.
  • Without the use of inheritance ,each class would have to explicitly include all of its features.
4.Polymerphism

  • Polymerphism is another important OOP concept.
  • .
  • Polymerphism means the ability to take more than one form.
  • For example ,an operation may exhibit different behavior in different instance.
  • The behavior depends upon the types of data used in the operation.
  • Polymerphism play an important role in allowing objects having different internal structures to share the same manner even though specific actions associated with each operation may differ.
  • Polymerphism is extensively used in implementing inheritance.

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