exercise2-21.lisp

(define (square-list items)
  (if (null? items)
    '()
    (cons (* (car items) (car items)) (square-list (cdr items)))))
(display (square-list (list 1 2 3 4)))
(newline)
(define (square-list items)
  (map (lambda (x) (* x x)) items))
(display (square-list (list 1 2 3 4)))
(newline)