public string reporte()
        {
            string    cdn  = "";
            ClaseBase temp = inicio;

            while (temp != null)
            {
                cdn += temp.ToString() + "\r\n";
                temp = temp.Siguiente;
            }
            return(cdn);
        }
        public string reporteInverso()
        {
            string    cdn  = "";
            ClaseBase temp = ultimo;

            while (temp != null)
            {
                cdn += temp.ToString() + "\r\n";
                temp = temp.Anterior;
            }

            return(cdn);
        }