;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-beginner-reader.ss" "lang")((modname list_append) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp")))))
;; list-append: list, list -> list
;; the function takes a list and returns
;; a new list which consists of all the elements
;; of the first list followed by all the elements
;; of the second list
;; Examples:
;; (list-append (cons 3 empty) (cons 5 empty)) -> 
;; (cons 3 (cons 5 empty))
;; (list-append (list 5 6 7) (list 3 6 0)) ->
;; (list 5 6 7 3 6 0)
(define (list-append list1 list2)
  (cond 
   [(empty? list1) list2]
   [else (cons (first list1) (list-append (rest list1) list2))]
  )
)

(list-append (list 5 6 7) (list 3 6 0))
;; expected
(list 5 6 7 3 6 0)

(list-append empty (list 5 6))
;; expected
(list 5 6)

(list-append empty empty)
;; expected
empty

;; list-reverse: list -> list
;; the function takes a list and returns a list
;; of the same elements, but in reverse order
;; Example:
;; (list-reverse (list 1 2 3 4 5)) -> (list 5 4 3 2 1)
(define (list-reverse a-list)
    (cond 
     [(empty? a-list) empty]
     [else (list-append (list-reverse (rest a-list)) (cons (first a-list) empty))]
    )
)

(list-reverse (list 1 2 3 4 5))
;; expected
(list 5 4 3 2 1)