(defparameter *array* (make-array 16 :initial-element NIL))

(defun prompt-read (prompt)
  (format *query-io* "~a: " prompt)
  (force-output *query-io*)
  (read *query-io*))

(defun get-values (&optional (prev-value 0))
  (if (>= prev-value 16) (format t "Page fault.")
    (progn (setf (elt *array* prev-value)
		 (prompt-read "Enter an integer. -1 to quit. "))
	   (if (not (= (aref *array* prev-value) -1))
	       (get-values (aref *array* prev-value))))))