map.rkt

#lang racket
(define lst '(1 2 3 4))
(define lst2 '(9 8 7 6 5 4 3 2 1 0))

(define (map proc items)
  (if (empty? items)
      empty
      (cons (proc (car items))
            (map proc (cdr items)))))
(define (square x)
  (* x x))


(define (scale-list items factor)
  (if (null? items)
      null
      (cons (* (car items) factor)
            (scale-list (cdr items) factor))))

(define (reverse lst)
  (reverse-iter lst (-(length lst)1) ))

(define (reverse-iter list length)
  (if (< length 0)
      empty
      ;;(get list 0)
      (cons (get list length) (reverse-iter list (- length 1)))
))


(define (length list)
  (length-iter list 0)
  )
(define (length-iter list count)
  (if (empty? list)
      count
      (length-iter (cdr list) (+ count 1))
      )
  )

(define (get lst index)
  (get-iter lst 0 index)
  )

(define (get-iter lst count index)
  (if (= index count)
      (car lst)
      (get-iter (cdr lst) (+ count 1) index)
      )
  )