Square Implementation from SICP

sqrt.clj

(defn square [x]
  (* x x))

(defn average [x y]
  (/ (+ x y) 2))

(defn improve [guess x]
  (average guess (/ x guess)))

(defn abs [x]
  (cond (< x 0) (- x)
        :else x))

(defn good-enough? [guess x]
  (println "good-enough? -> guess:" guess " , x:" x)
  (< (abs (- (square guess) x)) 0.001))

(defn sqrt [x]
  (defn sqrt-iter [guess x]
    (if (good-enough? guess x)
            guess
            (sqrt-iter (improve guess x)
                        x)))
  (sqrt-iter 1.0 x))