exam10.1.4

;; mht created on Nov 15, 2011

;; convert-euro : list-of-numbers -> list-of-numbers
;; exchange rate is 1.22 euro for each dollar
(define (convert-euro a-list-of-nums)
  (cond
    [(empty? a-list-of-nums) empty]
    [else
     (cons
      ( * 1.22 (first a-list-of-nums))
      (convert-euro (rest a-list-of-nums)))]))

;; test
(convert-euro (cons 10 (cons 20 empty)))

;; convert-euro :  number list-of-numbers  -> list-of-numbers
(define (convert-euro-1  rate a-list-of-nums)
  (cond
    [(empty? a-list-of-nums) empty]
    [else
     (cons
      ( * rate (first a-list-of-nums))
      (convert-euro-1  1.22 (rest a-list-of-nums)))]))

;; test
(convert-euro-1 1.22 (cons 10 (cons 20 empty)))