1
版本信息计算奇怪的输出:版本4.9.0.1(稳定性/ 4.9.0)(REV 8b3189b)MACOSX-UNIX的铛,X86-64用PI鸡方案
的代码实际上是锻炼1.3 .1 SICP:
(define (product term a next b)
(define (iter a result)
(if (> a b)
result
(iter (next a) (* (term a) result))
)
)
(iter a 1)
)
(define (get-pi n)
(define (next x) (+ x 2))
(define (term x) (* x x))
(* 8 n (/ (product term 4 next n) (product term 3 next (+ n 1))))
)
输出:
#;102> (get-pi 165)
3.13208714360219
#;103> (get-pi 167)
3.13220081034665
#;104> (get-pi 169)
3.13231179078142
#;105> (get-pi 170)
0.0
为什么结果变成了0.0≦
谢谢!