How to return a list of numbers between 1 and x

Question

I'm trying to create a function that takes in user input, x, and displays all of the numbers from 1 up to x. Not quite sure where to go from here:

(define (iota x)
     (if (>= x 1)
        (display

Answer 1

;; Takes a number n
;; and returns a list with 1..n
;; in order.
(define (make-list n)
  (let loop ((n n) (accumulator '()))
    (if (zero? n)
        accumulator
        (loop (- n 1) (cons n accumulator)))))

;; prints data and adds
;; a newline
(define (println x)
  (display x)
  (newline))

;; prints 1..n by applying println 
;; for-each element over the list 1..n
(define (iota n)
  (for-each println (make-list n)))

Answer 2

Basically you want to use recursion. So think of it was counting up. As you count up either you've added enough numbers and you are done building your list or you need to add the current number to your list and go on to the next number.

Look at the following code:

(define (range-2 next-num max-num cur-list)
        ;;if we've added enough numbers return               
        (if (> next-num max-num)
            cur-list
            ;; otherwise add the current number to the list and go onto the next one
            (range-2
                (+ 1 next-num)
                max-num
                (append cur-list (list next-num))
            )))

But to get the function you wanted you need to start off with the constants you specified (ie 1), so lets create a convenience function for calling range with the starter values you need to set up the recursion, sometimes called priming the recursion:

(define (range X)
    (range-2 1 X `() ))

You could do it without the second function using lambda, but this is pretty common style from what I've seen.

Once you've constructed a list of the numbers you need you just display it using

(display (range 10))