Object Oriented Programming

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All are things in the world are objects. We can identify these things easily but we don’t care about their inside.
This is the fact to introduce Object Oriented Programming. In a program, we can use a system as an object. It is easy to solve problems in programming because object abstracts the entire thing and represent as a unit. In an object, data are covered by methods. So other objects cannot connect with data directly.

There are some features in this Object Oriented Programming.
  •      We can divide a program to many objects.
  •       We can add new data and methods easily on the time.
  •       Data are hidden and external things cannot connect with them.
  •       Data highlight than process.

Basic Concepts of object oriented programming

1. Object and Class
Object: Object is the thing which we can see and touch. In the programming these are the basic units. An object has three parts.
  •     Identify: A name to identify from others.
  •     State: Properties of the object.
  •     Behaviors:  Things that the object can do.
     Example : Postman
       State:
       Uniform, Letters, Post-cards, Post-bag

 Behaviors:
              Deliver post-cards and letters, Open the public post boxes

Class: Objects with same structure and behavior are categorized into a class. A class has objects with same template.  So we can introduce a class as a template. We use a class to add new object to the program.



2. Abstraction
 Abstraction is the process that knows which details to hide away and which to present. Hides details are not important in programming. This is useful to deal with complex problems.

3. Encapsulation

Encapsulation is a method of abstraction. Wrapping methods and data together into a single unit is known as encapsulation.
In programming, we use “private” code to encapsulation. Encapsulated object act as a black box. 

4. Inheritance
Hierarchical relationship between super class and sub class is called as inheritance. Every sub class has all the properties of its super class and its unique properties. Inheritance supports the hierarchical classification. 

      5. Polymorphism
Polymorphism means the ability to take more than one form. An operation may exhibit different behaviors which depend on the data types and methods used in the operation.




   6.  Message Communication
      An object can communicate with one or more objects by sending and receiving information, such as people do. There are sending objects and receiving objects. This communication helps to bind all the objects as a system.

Object has a life cycle. We can only communicate while it is alive. Sometimes, “message passing” helps to start objects operations.

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