Callback Function in C#

Definition:

-------------

       >> Functions that are triggered when an associated event happens.

Example :

------------

  > In C, function pointer is used as a callback functions.

  > In C++, virtual function is used as a callback function.

  > c#, delegate keyword is used to create a call back function.

Example in c#:

------------------

using System;

using System.Collections.Generic;

using System. Text;

namespace ConsoleApplication1

{

    class Program

    {

        public delegate int execute(int a, int b); //declare a delegate method

        static void Main(string[] args)

        {

            Program p = new Program();     

            execute ex = new execute(p.add);

            Console.WriteLine(ex(2,3));  //add method is executed

            ex = new execute(p.subtract);

            Console.WriteLine(ex(2, 3)); //subtract method is executed            

        }

        public int add(int a, int b)

        {

            return (a + b);

        }

        public int subtract(int a, int b)

        {

            return (a - b);

        }

    }

}