What is Information hiding in object oriented programming?

After discussing the c++ class and objects in detail now we will move toward the design principles of object oriented programming.

Design Principles of Object Oriented Programming:

  

There are 5 design principle of object oriented programming as

   (1) Information hiding

   (2) Encapsulation

   (3) Abstraction

   (4) Inheritance

   (5) Polymorphism

  These 5 concepts are the back bone of object oriented programming and we can say its foundation is based on these principles.

I know it is very difficult for the newbies to grasp these concepts so I will try to explain these principles in details and by giving relevant examples from the real life.

Let’s first explain the information hiding.

Information Hiding

Information hiding is the technique in which we try to hide the attributes of the object from outside world.

According to this technique information in whatever form is stored inside the object and it is hidden from the outside world and only object itself manipulate its state or data and we cannot directly access them. We need an interface to access them.

Information hiding is achieved by using access specifies a topic we will study in details in upcoming tutorials.

    Examples of Information Hiding

 Information Hiding has plenty of examples related to the real life.

  Suppose myself jawad tariq is an object. Human is a very complicated object because it has every requirement  which is needed for an object.  Now I use information hiding technique as you the outer world do not know about my personal life. You do not know from where i belong, you do not know my marital status and you do not know either I have kids or not. This is because I have made all these information hidden. This information is saved inside my brain at some part of it and you the outer world have no direct access to it. I have not put a label on my forehead which tell you what is my age or what is marital status etc. You can only access to my private data using the interface I have provided you .Consider that I  have provided you an interface to find my age "What is your age" you  can access to my private data indirectly by using that interface. So object has made all its information hidden so other objects cannot directly manipulate their states.

Information Hiding Advantages

    (1) Information hiding detail simplifies the modal by hiding complex details and implementation               from you.

    (2) Information hiding technique will not allow the user to manipulate states of object directly hence this technique avoids the object to go into the invalid state.

Let me elaborate my second point with some examples.  Consider a class student for sake of simplicity considers it has only one attribute age. Now what will happen if user enters   a negative value for age?  User may know that age is always in positive integer but he may accidently or unintentionally press negative key. So this will leads the object in to invalid state. Here information hiding is useful as it do not give direct access to the user to manipulate the data. User can only manipulate the data using an interface or a member function. Now you may have a question that how member function will act to reduce chances of object to go into invalid state. I will explain this when we will go further into object oriented programming. At that moment we are only discussing the concepts of object oriented programming which I think are very necessary for you to feel comfortable with object oriented programming in c++.

Note:      

          If you have further queries about “concept of objects” you can email me at jawad1647@gmail.com, I will try to solve all your queries and also please don’t hesitate to report mistakes as you know "to err is a human". You can report the errors by sending me a mail at the email address given above.