SICP solution exercise 2.33

Solution for exercise 2.33 of SICP:

(define nil '())

(define (square x)
  (* x x))

(define (accumulate op initial sequence)
  (if (null? sequence)
      initial
      (op (car sequence)
          (accumulate op initial (cdr sequence)))))

(define (map p sequence)
  (accumulate (lambda (x y) (cons (p x) y)) nil sequence))

(define (append seq1 seq2)
  (accumulate cons seq2 seq1))

(define (length sequence)
  (accumulate (lambda (x y) (+ 1 y)) 0 sequence))

;--------------------tests-------------------------

(map square (list 1 2 3))
(append (list 1 2 3) (list 4 5 6))
(length (list 5 6 7 8 9))

This entry was posted in SICP and tagged , . Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>