;; This buffer is for text that is not saved, and for Lisp evaluation.
;; To create a file, visit it with ‘C-x C-f’ and enter text in its buffer.

(defun cg103 (text len)
  (with-temp-buffer
    (insert text)
    (setq fill-column len)
    (fill-region (point-min) (point-max))
    (buffer-string)))