Check out the code below:

using System.Linq;
class Program
{
  static void Main()
  { 
      int[] data = { 1, 2, 3, 1, 2, 1 };
      foreach (var m in from m in data orderby m select m)
            System.Console.Write(m);
  }
}

Now, the question is:

  Is this code valid or not??

  If valid, how?

  If not valid, why?

(Source: Eric Lippert’s Blog)