sicp练习1.21用smallest-divisor寻找最小因子
(define (square x) (* x x))(define (smallest-divisor n) (find-divisor n 2))(define (find-divisor n test-divisor) (cond ((> (square test-divisor) n) n) ((divides? test-divisor n) test-divisor) (else (find-divisor n (+ test-divisor 1)))))(define (divides? a b) (= (remainder b a) 0)) (smallest-divisor 199)(smallest-divisor 1999)(smallest-divisor 19999)得出的结论是199的最小因子是199；1999的最小因子是1999；而19999的最小因子是17?
