Purpose of Delegate And Captured variable in C#.

Demonstrate a captured variable.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace DemoCapture

{

    // This delegate returns int and takes an int argument. 

    delegate int CountIt(int end);

    class VarCapture

    {

        static CountIt counter()

        {

            int sum = 0;

            // Here, a summation of the count is stored 

            // in the captured variable sum. 

            CountIt ctObj = delegate(int end)

            {

                for (int i = 0; i <= end; i++)

                {

                    Console.WriteLine(i);

                    sum += i;

                }

                return sum;

            };

            return ctObj;

        }

        class Program

        {

            static void Main(string[] args)

            {

                // Get a counter 

                CountIt count = counter();

                int result;

                result = count(3);

                Console.WriteLine("Summation of 3 is " + result);

                Console.WriteLine();

                result = count(5);

                Console.WriteLine("Summation of 5 is " + result);

                Console.ReadKey();

            }

        }

    }

}

Purpose of Delegate

- It supports event programming

- It gives the program a way to execute a method at runtime without having to know

precisely what that method is at compile time.