private static void PerformLinkedListOps()
        {
            var linkedList = new LinkedLists <int>();

            linkedList.AddFirst(1);
            linkedList.AddFirst(0);
            linkedList.AddLast(-1);
            linkedList.AddLast(4);
            linkedList.Print();
            Console.WriteLine(linkedList.getKthFromTheEnd(2));
            Console.WriteLine("Reverse");
            linkedList.Reverse();
            linkedList.Print();
            linkedList.DeleteFirst();
            linkedList.DeleteLast();
            Console.WriteLine(linkedList.Contains(1));
            Console.WriteLine(linkedList.Contains(21));
            Console.WriteLine(linkedList.IndexOf(1));
            Console.WriteLine(linkedList.IndexOf(21));
            Console.WriteLine(linkedList.ToArray());
            linkedList.Print();
            Console.ReadLine();
        }