Delegates

Delegate is a method or an object that refers to a method. A delegate provides a mean to encapsulate a method. A delegate holds a reference to a method and used to invoked the method.

Program of Delegate in Static Manner: Simple Console application
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Delegates
{
    class Program
    {
        static void Main(string[] args)
        {
            int a, b, result;
            Intops intop;
            Console.WriteLine("\n Enter 2 integer");
            Console.Write("a-");
            a = Convert.ToInt32(Console.ReadLine());
            Console.Write("a-");
            b = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("b-");
            intop = new Intops(add);
            result = intop(a, b);
            Console.WriteLine("Addition-" + result);

            intop = new Intops(sub);
            result = intop(a, b);
            Console.WriteLine("Substraction-" + result);

            intop = new Intops(div );
            result = intop(a, b);
            Console.WriteLine("Division-" + result);

            intop = new Intops(mul);
            result = intop(a, b);
            Console.WriteLine("Multiplication-" + result );

            Console.ReadLine();

        }
        delegate int Intops(int x, int y);
        static  int add(int a, int b)
        { return a + b;}
        static int sub(int a, int b)
        { return a - b; }
        static int div(int a, int b)
        { return a / b; }
        static int mul(int a, int b)
        { return a * b; }
    }
}
Output:

Program of Delegate in Instance Manner:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Delegate2
{
    delegate int Intops(int a,int b);
    class Program
    {
        static void Main(string[] args)
        {
            int a, b, result;
            Intops intop;
            Program p = new Program();
            Console.WriteLine("\n Enter 2 integer");
            Console.Write("a-");
            a = Convert.ToInt32(Console.ReadLine());
            Console.Write("a-");
            b = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("b-");
            intop = p.add;
            result = intop(a, b);
            Console.WriteLine("Addition-" + result);

            intop = p.sub;
            result = intop(a, b);
            Console.WriteLine("Substraction-" + result);

            intop = p.div;
            result = intop(a, b);
            Console.WriteLine("Division-" + result);

            intop = p.mul;
            result = intop(a, b);
            Console.WriteLine("Multiplication-" + result);

            Console.ReadLine();


        }

        public  int add(int a, int b)
        { return a + b; }
        public int sub(int a, int b)
        { return a - b; }
        public int div(int a, int b)
        { return a / b; }
        public int mul(int a, int b)
        { return a * b; }
    }
}
Output:
output will be similar like above.