lec_4 pag 64

[barld]

example in slides of an interface has already an implementation. In C# it is not aloud quote C# reference:

Interfaces Summary
An interface has the following properties:

• An interface is like an abstract base class. Any class or struct that implements the interface must implement all its members.
• An interface can't be instantiated directly. Its members are implemented by any class or struct that implements the interface.
• Interfaces can contain events, indexers, methods, and properties.
• _Interfaces contain no implementation of methods._
• A class or struct can implement multiple interfaces. A class can inherit a base class and also implement one or more interfaces.

https://msdn.microsoft.com/en-us/library/ms173156.aspx#Anchor_0