Bagaimana untuk menukar dua nombor dalam C# tanpa menggunakan pembolehubah sementara

val1 = 5;
val2 = 10;

val1 = val1 + val2;
val2 = val1 - val2;
val1 = val1 - val2;

using System;
namespace Demo {
   class Program {
      static void Main(string[] args) {

         int val1,val2;
         val1 = 5;
         val2 = 10;

         Console.WriteLine("Values before swap...");
         Console.WriteLine(val1.ToString());
         Console.WriteLine(val2.ToString());

         val1 = val1 + val2;
         val2 = val1 - val2;
         val1 = val1 - val2;

         Console.WriteLine("Values after swap...");
         Console.WriteLine(val1.ToString());
         Console.WriteLine(val2.ToString());
         Console.ReadLine();
      }
   }
}