c# events handler geeksforgeeks

// C# program to illustrate the use of Delegates 
using System; 
namespace GeeksForGeeks { 
      
// declare class "Geeks" 
class Geeks { 
      
// Declaring the delegates 
// Here return type and parameter type should  
// be same as the return type and parameter type 
// of the two methods 
// "addnum" and "subnum" are two delegate names 
public delegate void addnum(int a, int b); 
public delegate void subnum(int a, int b); 
      
    // method "sum" 
    public void sum(int a, int b) 
    { 
        Console.WriteLine("(100 + 40) = {0}", a + b); 
    } 
  
    // method "subtract" 
    public void subtract(int a, int b) 
    { 
        Console.WriteLine("(100 - 60) = {0}", a - b); 
    } 
  
// Main Method 
public static void Main(String []args) 
{ 
      
    // creating object "obj" of class "Geeks" 
    Geeks obj = new Geeks(); 
  
    // creating object of delegate, name as "del_obj1"  
    // for method "sum" and "del_obj2" for method "subtract" & 
    // pass the parameter as the two methods by class object "obj" 
    // instantiating the delegates 
    addnum del_obj1 = new addnum(obj.sum); 
    subnum del_obj2 = new subnum(obj.subtract); 
  
    // pass the values to the methods by delegate object 
    del_obj1(100, 40); 
    del_obj2(100, 60); 
  
    // These can be written as using 
    // "Invoke" method 
    // del_obj1.Invoke(100, 40); 
    // del_obj2.Invoke(100, 60); 
} 
} 
} 

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; namespace event_programming{    //This is Subscriber Class    class Program    {        static void Main(string[] args)        {            AddTwoNumbers a = new AddTwoNumbers();            //Event gets binded with delegates            a.ev_OddNumber += new AddTwoNumbers.dg_OddNumber(EventMessage);            a.Add();            Console.Read();        }              //Delegates calls this method when event raised.          static void EventMessage()        {            Console.WriteLine("********Event Executed : This is Odd Number**********");        }    }    //This is Publisher Class    class AddTwoNumbers    {                public delegate void dg_OddNumber(); //Declared Delegate             public event dg_OddNumber ev_OddNumber; //Declared Events         public void Add()        {            int result;            result = 5 + 4;            Console.WriteLine(result.ToString());            //Check if result is odd number then raise event            if((result % 2 != 0) && (ev_OddNumber != null))            {                ev_OddNumber(); //Raised Event            }                  }    }}