Re: [Haskell-cafe] How to calculate de number of digits of an integer? (was: Is logBase right?)

Am Mittwoch 26 August 2009 06:29:47 schrieb George Pollard:

You could also fudge the input:

{-# LANGUAGE NoMonomorphismRestriction #-}

log10 = floor . logBase 10 . (0.5+) . fromIntegral

numDigits n | n < 0 = 1 + numDigits (-n) numDigits 0 = 1 numDigits n = 1 + log10 n

-- checked [0..10^8], finding a counter-example is left as an exercise :P

Prelude> numDigits (10^15) 15