On Aug 24, 2007, at 9:18 , Arie Groeneveld wrote:
Hi, I defined several functions for calculating the number of trailing zero's of n! tm = sum . takeWhile(>0) . iterate f . f where f = flip div 5 tm1 n = sum . takeWhile(>0) . map (div n . (5^)) $ [1..] tm2 n = sum . takeWhile(>0) . map (div n) $ iterate ((*)5) 5 tm3 = sum . takeWhile(>0) . flip map (iterate ((*)5) 5) . div Questions: Which one is the most elegant one generally speaking? Which one is most natural in Haskell? Is there more 'beauty' to possible? My personal choice is 'tm'. I like 'tm3' (a revised version of tm2) in terms of pointlessness and not having a 'where', but I think it's a bit contrived because of the 'flip'. Comments?
Here's a much more inefficient version, but it has the merit of being very easy to understand:
tm_silly n = length $ takeWhile (=='0') $ reverse $ show $ product [1..n]
/Björn _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
