An interface class can be member of namespace or class can. Interface class can contain signatures for the following members.
A class should implement interface members are specified in interface class. An example is given below to clear more view about interface class.
Class Test: AbcInterface
Static Void Main()
//Declaring the interface instance
AbcInterface obj = new Test ();
//Calling the member
In short interface class provides great flexibility to design application & reduces the complexity of the application. It is highly recommended to use object oriented mythologies (OOPS) to make application more robust with neat & clean code.
Here is explained deeply Abstraction class and explained completely step by step difference between Interface and Abstraction Class