Some days ago I ask me 'How can I create function that tell me if is a prime number or not, today I have created a simple function, so I would like to share it.'
I think that there are a lot of functions with the same result but I like doing code to know how it works.
(defun prime-number-p (number)
"Returns true if the number is prime; otherwise returns false"
(let ((counter 2)); the second prime number
(cond
;; special case
;; the definition of prime number
((equal number 1)
nil)
;; is a natural number which has exactly two distinct natural number divisors:
;;1 and itself.
;; apply the prime number definition
(t
(loop
(when (equal counter number)
(return t))
(if (= (mod number counter) 0)
(return nil))
(incf counter))))))
You can view the code :
