;; a parameter cannot be changed in Clojure: there are no "out" parameters.
;; the answer leaves the function through the return value
(defn get-sum [n1 n2]
  (+ n1 n2))

(def sum (get-sum 5 3))
;; sum is 8
(println "sum is" sum)

;; two answers at once come back in a vector and are destructured
(defn divide [a b]
  [(quot a b) (rem a b)])

(let [[quotient remainder] (divide 17 5)]
  (println "quotient is" quotient)
  (println "remainder is" remainder))