Mapping

mapping.scm

; 2.21

(define (square-list1 items)
  (if (null? items)
      null
      (cons (* (car items) (car items)) (square-list1 (cdr items)))
      )
  )

(define (square-list2 items)
  (map (lambda (x) (* x x)) items)
  )

(square-list1 (list 1 2 3 4))
(square-list2 (list 1 2 3 4))