using System;

using System.Linq;                  

public class Program

{

    public static void Main()

    {

        string[] oldname = new[] { "arun", "jack", "tom" , "tom" };

        string[] newname = new string[] { "jack", "hardy", "arun", "hardy","arun"};

        var distinctInOld = oldname.Except(newname);

        var distinctInNew = newname.Except(oldname);

        Console.WriteLine("Distinct items in Old: {0}", String.Join(",",distinctInOld));

        Console.WriteLine("Distinct items in New: {0}", String.Join(",",distinctInNew));

    }

}