Interface in C# with example

Interface: 

Mainly Interface used in C# for achieving multiple inheritance. As .net does not support multiple inheritance.

In interface we define methods and we will implement in derived classes.

• An interface cannot inherit from a class. 
• An interface can inherit from multiple interfaces. 
• A class can inherit from multiple interfaces, but only one class. 
• Interface members must be methods, properties, events, or indexers. 
• All interface members must have public access (the default). 
• By convention, an interface name should begin with an uppercase I.

Example:

using System;

interface inter1

{

    void greet();

}

interface inter2 : inter1

{

    void display();

}

interface inter3 : inter2

{

    void show();

}

class demo : inter3

{

    public void greet()

    {

        Console.WriteLine("Method from inter1");

    }

    public void display()

    {

        Console.WriteLine("Method from inter2");

    }

    public void show()

    {

        Console.WriteLine("Method from inter3");

    }

    public static void Main()

    {

        inter3 i = new demo();

        i.greet(); i.display(); i.show();

    }

}