Haskell

fizzbuzz.hs

-- A nice collection of FizzBuzz implementations
-- GistID: 5313582

module Main where

import Data.List

fb :: (Show a, Integral a) => a -> String
fb i
    | i `rem` 15 == 0 = "FizzBuzz"
    | i `rem` 5  == 0 = "Buzz"
    | i `rem` 3  == 0 = "Fizz"
    | otherwise = show i


fb2 :: (Show a, Integral a) => a -> String
fb2 i = let buzz = if i `rem` 5 == 0 then "Buzz" else ""
            fizz = if i `rem` 3 == 0 then "Fizz" else ""
            num = if null (fizz ++ buzz) then show i else ""
        in fizz ++ buzz ++ num


fb3 :: (Show a, Integral a) => ([String], a, a) -> a -> ([String], a, a)
fb3 (s, 3, 5) _ = ("FizzBuzz":s, 1, 1)
fb3 (s, 3, five) _ = ("Fizz":s, 1, five+1)
fb3 (s, three, 5) _ = ("Buzz":s, three+1, 1)
fb3 (s, three, five) i = (show i:s, three+1, five+1)


fb4 :: (Show a, Integral a) => a -> String
fb4 i | null desc = show i
      | otherwise = desc
  where
    desc = concat [ label | (j, label) <- tags, i `rem` j == 0]
    tags = sort [(3, "Fizz"), (5, "Buzz")]


main1 = mapM_ (putStrLn . fb) [1..20]
main2 = mapM_ (putStrLn . fb2) [1..20]
main3 = let fst3 (a,_,_) = a in mapM_ putStrLn . reverse . fst3 $ foldl fb3 ([],1,1) [1..20]
main4 = mapM_ (putStrLn . fb4) [1..20]

main = main1