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NumberCheck in haskell 


import System.Environment
import Data.Char

main = do
   arg:_ <- getArgs
   putStrLn (arg ++ " is " ++ (result arg))
   where result arg = if check arg then "correct" else "incorrect"
         check arg = dotOrDigit `all` arg && oneOrZeroDots arg
         dotOrDigit = (`elem` ['0'..'9'] ++ ['.'])
         oneOrZeroDots = (<=1) . length . (filter ('.'==))

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