How to do exponentiation in clojure?

Question

How can I do exponentiation in clojure? For now I\'m only needing integer exponentiation, but the question goes for fractions too.

Answer 1

SICP inspired full iterative fast version of 'sneaky' implementation above.

(defn fast-expt-iter [b n]
  (let [inner (fn [a b n]
                (cond
                  (= n 0) a
                  (even? n) (recur a (* b b) (/ n 2))
                  :else (recur (* a b) b (- n 1))))
        ]
    (inner 1 b n)))