Encapsulation vs Abstraction?

Abstraction is the concept of describing something in simpler terms, i.e abstracting away the details, in order to focus on what is important (This is also seen in abstract art, for example, where the artist focuses on the building blocks of images, such as colour or shapes). The same idea translates to OOP by using an inheritance hierarchy, where more abstract concepts are at the top and more concrete ideas, at the bottom, build upon their abstractions. At its most abstract level there is no implementation details at all and perhaps very few commonalities, which are added as the abstraction decreases.

As an example, at the top might be an interface with a single method, then the next level, provides several abstract classes, which may or may not fill in some of the details about the top level, but branches by adding their own abstract methods, then for each of these abstract classes are concrete classes providing implementations of all the remaining methods.

Encapsulation is a technique. It may or may not be for aiding in abstraction, but it is certainly about information hiding and/or organisation. It demands data and functions be grouped in some way - of course good OOP practice demands that they should be grouped by abstraction. However, there are other uses which just aid in maintainability etc.

encapsulation is a part of abstraction or we can say its a subset of abstraction

They are different concepts.

• Abstraction is the process of refining away all the unneeded/unimportant attributes of an object and keep only the characteristics best suitable for your domain.

  E.g. for a person: you decide to keep first and last name and SSN. Age, height, weight etc are ignored as irrelevant.

  Abstraction is where your design starts.

• Encapsulation is the next step where it recognizes operations suitable on the attributes you accepted to keep during the abstraction process. It is the association of the data with the operation that act upon them.
  I.e. data and methods are bundled together.

Encapsulation is hiding unnecessary data in a capsule or unit

Abstraction is showing essential feature of an object

Encapsulation is used to hide its member from outside class and interface.Using access modifiers provided in c#.like public,private,protected etc. example:

Class Learn
{
  private int a;         // by making it private we are hiding it from other
  private void show()   //class to access it
  {
   console.writeline(a);
  }
}

Here we have wrap data in a unit or capsule i.e Class.

Abstraction is just opposite of Encapsulation.

Abstraction is used to show important and relevant data to user. best real world example In a mobile phone, you see their different types of functionalities as camera, mp3 player, calling function, recording function, multimedia etc. It is abstraction, because you are seeing only relevant information instead of their internal engineering.

 abstract class MobilePhone
    {
        public void Calling();       //put necessary or essential data
        public void SendSMS();       //calling n sms are main in mobile
    }

    public class BlackBerry : MobilePhone   // inherited main feature
    {
        public void FMRadio();            //added new
        public void MP3();
        public void Camera();
        public void Recording();

    }

Encapsulation is a strategy used as part of abstraction. Encapsulation refers to the state of objects - objects encapsulate their state and hide it from the outside; outside users of the class interact with it through its methods, but cannot access the classes state directly. So the class abstracts away the implementation details related to its state.

Abstraction is a more generic term, it can also be achieved by (amongst others) subclassing. For example, the interface List in the standard library is an abstraction for a sequence of items, indexed by their position, concrete examples of a List are an ArrayList or a LinkedList. Code that interacts with a List abstracts over the detail of which kind of a list it is using.

Abstraction is often not possible without hiding underlying state by encapsulation - if a class exposes its internal state, it can't change its inner workings, and thus cannot be abstracted.