using System;

​

public delegate void Calculate(int a, int b);

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        int x = 10;

        int y = 5;

        Calculate c1 = Calculator.Sum;

        //multicast delegate

        //c1 += Calculator.Diff;

        //c1 += Calculator.Multiply;

        //call delegate functions in sequence

        //c1.Invoke(x, y);

        //pass delegate as parameter

        DoOperation(x,y,c1);

    }

    private static void DoOperation(int a, int b, Calculate opp)

    {

        opp.Invoke(a,b);

    }

}

​

public static class Calculator

{

    public static void Sum(int a, int b)

    {

        Console.WriteLine("Sum = " + (a+b));

    }

    public static void Diff(int a, int b)

    {

        Console.WriteLine("Diff = " + (a-b));

    }

    public static void Multiply(int a, int b)

    {

        Console.WriteLine("Sum = " + (a*b));

    }

}