/// <summary>
        /// Entry point into console application.
        /// </summary>
        public void Execute()
        {
            // Setup Chain of Responsibility
            Approver larry = new Director();
            Approver sam   = new VicePresident();
            Approver tammy = new President();

            larry.SetSuccessor(sam);
            sam.SetSuccessor(tammy);

            // Generate and process purchase requests
            Purchase p = new Purchase(2034, 350.00, "Assets");

            larry.ProcessRequest(p);

            p = new Purchase(2035, 32590.10, "Project X");
            larry.ProcessRequest(p);

            p = new Purchase(2036, 122100.00, "Project Y");
            larry.ProcessRequest(p);
        }
        /// <summary>
        /// Entry point into console application.
        /// </summary>
        private static void Main()
        {
            // Setup Chain of Responsibility
              Approver larry = new Director();
              Approver sam = new VicePresident();
              Approver tammy = new President();

              larry.SetSuccessor(sam);
              sam.SetSuccessor(tammy);

              // Generate and process purchase requests
              Purchase p = new Purchase(2034, 350.00, "Assets");
              larry.ProcessRequest(p);

              p = new Purchase(2035, 32590.10, "Project X");
              larry.ProcessRequest(p);

              p = new Purchase(2036, 122100.00, "Project Y");
              larry.ProcessRequest(p);

              // Wait for user
              Console.ReadKey();
        }