作者 Anonymous [actionscript] 2012-01-14 10:54 (点击下载)

-- Inspired by SICP
 
fac1 1 = 1
fac1 n = n * fac1 (n - 1)
 
fac2 n = fac_iter 1 1
    where
        fac_iter pro cnt
            | cnt > n = pro
            | otherwise = fac_iter (cnt * pro) (cnt + 1)