Difference between Interface, abstract class, sealed class, static class and partial class in C#? [closed]

Question

Difference between Interface, abstract class, sealed class, static class and partial class in c#? If all classes available in vb.net?

Answer 1

• abstract class
  Should be used when there is a IS-A relationship and no instances should be allowed to be created from that abstract class. Example: An Animal is an abstract base class where specific animals can be derived from, i.e. Horse, Pig etc. By making Animal abstract it is not allowed to create an Animal instance.

• interface
  An interface should be used to implement functionality in a class. Suppose we want a horse to be able to Jump, an interface IJumping can be created. By adding this interface to Horse, all methods in IJumping should be implemented. In IJumping itself only the declarations (e.g. StartJump and EndJump are defined), in Horse the implementations of these two methods should be added.

• sealed class
  By making Horse sealed, it is not possible to inherit from it, e.g. making classes like Pony or WorkHorse which you like to be inheriting from Horse.

• static class
  Mostly used for 'utility' functions. Suppose you need some method to calculate the average of some numbers to be used in the Horse class, but you don't want to put that in Horse since it is unrelated and it also is not related to animals, you can create a class to have this kind of methods. You don't need an instance of such a utility class.

• partial class
  A partial class is nothing more than splitting the file of a class into multiple smaller files. A reason to do this might be to share only part of the source code to others. If the reason is that the file gets too big, think about splitting the class in smaller classes first.