Question

Possible Duplicates:
Interface vs Base class
Interface or abstract class?

Hi All,

I am just thinking about the abstract classes and interfaces, I know how they work technically but i don’t understand the real use of abstract classes and interfaces.
I mean why should we use abstract classes when we know that we can’t create it’s object, we have to anyway extend this class to use it so why don’t we put everything in the derived class.

Same is with interfaces, we have to implement the interface so why don’t we put all the methods which are defined in the interface in the class in which we implement the interface.

Can someone please clear my doubts with some examples ?

Answer 1

Links at Stackoverflow

• Exact use of Abstract class
• Interface or abstract class?
• Abstract classes vs Interfaces
• Why do both the abstract class and
  interface exist in .Net?
• differences between an abstract class
  and an interface in C#
• What’s the difference between an
  interface and an abstract class?
• When to use an interface instead of
  an abstract class and vice versa?
• Help me understand in a practical
  example the usage abstract classes vs
  interfaces?

Others

• Abstract Class versus Interface
• Should I use an abstract class or an
  interface?
• Abstract base class over interface
• Learn This: When to use an Abstract
  Class and an Interface
• Recommendations for Abstract Classes
  vs. Interfaces – MSDN
• Working with Abstract classes, Sealed
  Classes, and Interfaces in C#
• Difference between Abstract class and
  Interface in C# (.Net)