C# example to swap two numbers without using third variable

 using System;  
 using System.Collections.Generic;  
 using System.Linq;  
 using System.Text;  
 using System.Threading.Tasks;  
 namespace ConsoleApp2  
 {  
   class Swap  
   {  
     public static void Main(string[] args)  
     {  
       int a = 5, b = 10;  
       Console.WriteLine("Before swap a= " + a + " b= " + b);  
       a = a * b; //a=50 (5*10)     
       b = a / b; //b=5 (50/10)     
       a = a / b; //a=10 (50/5)    
       Console.Write("After swap a= " + a + " b= " + b);  
     }  
   }  
 }