What is abstraction? What are the different ways to achieve abstraction?

• Abstraction is one of the characteristic features of Object Oriented Programming.
• Abstraction enforces the rule that a component "exposes only which is required for the context".
• This ensures a proper layer of view, where the client is provided with access to those features or contents of it which are needed for the moment.
• In C#, abstraction is achieved in two ways: by the use of abstract classes and interfaces.
• An abstract class is a class which can't be instantiated but is extended by its sub classes which create different versions of the functionality defined in the abstract class.
• An interface is like a contract - it only contains a template of how the component would look like, and all its sub classes must implement the same design.
• Abstract classes are used to create base functionality with a scope for further extension, while interfaces are created to use while interacting with other components without having to use concrete types that contain functionality.

Object Oriented Programming Concepts - Abstraction