快速求幂 sicp练习1.16

(define (even? n)  (= (remainder n 2) 0))(define (fast-expt-iter result b n)  (cond ((= n 0) 1)        ((= n 1) (* result b))        ((even? n) (fast-expt-iter result (* b b) (/ n 2)))        (else(fast-expt-iter (* b result) b (- n 1)))))(define (fast-expt b n)  (fast-expt-iter 1 b n) )(fast-expt 2 0)(fast-expt 2 1)(fast-expt 2 5)(fast-expt 2 6)