using System;

public class Program

{

    public static void Main()

    {

        var tokens = new object[] { 1, 2, 3, 4, 5, 6, 7, 8 };

        object prev = null;

        object current = null;

        int i = 0;

        foreach (var next in tokens)

        {

            if (i > 0)

            {

                Console.WriteLine("Processing {0}. Prev = {1}. Next = {2}", current, prev, next);

            }

​

            prev = current;

            current = next;

            i++;

        }

​

        // Process the final item

        Console.WriteLine("Processing {0}. Prev = {1}. Next = {2}", current, prev, null);

    }

}