Assignment in elisp

Question

I'm trying to learn elisp. I wanted to use (random n) and then take the result of (random n) and use it to compute a new random number until we reach 1.

Something like this:

(random 100)
99
(random 99)
51
(random 51)
24
(random 24)
11
(random 11)
3
(random 3)
2
(random 2)
1

How do I assign, the new value of n to (random n) ?

(setq n (random n))

does not work. This gives a constant number, (random n) is not calculated.

Can you give me a hint? I realize this is a total newbie question. Thanks.

EDİT

(defun rnd (n)       
  (setq counter 0)
  (let ((ret ()))
            
    (while (< 1 n)
      
      (setq n (random n))
      (setq counter (+ counter 1))  
      (push n ret))
    
    
    (reverse ret))
  )

(format "list: %s \n steps: %s" (rnd 100000) counter)

Answer 1

You cannot change the value of an external variable from within a function:

(defvar n 100)
(defun rnd (n)
  (setq n (random n)))

(rnd n) will not change the value of n because rnd create a new binding for n.

This, however, should work:

(defvar n 100)
(defun rnd ()
  (setq n (random n)))

Or you can just do a loop inside rnd:

(defun rnd (n)
  (let ((ret ()))
    (while (< 1 n)
      (setq n (random n))
      (push n ret))
    ret))
(rnd 100)
==> (1 3 8 16 20 27 53)