-- Do the game fizzbuzz (http://en.wikipedia.org/wiki/Fizz_buzz).
-- Return a string counting from 1 to the specified number.
-- Replace numbers dvisible by 3 with "fizz" and numbers divisible
-- by 5 with "buzz".  If a number is divisible by both 3 and 5,
-- replace it with "fizzbuzz".

fb :: Int -> String
fb x | mod x 3 == 0 && mod x 5 == 0 = "fizzbuzz"
fb x | mod x 3 == 0 = "fizz"
fb x | mod x 5 == 0 = "buzz"
fb x = show x

fizzbuzz :: Int -> String
fizzbuzz n
	| n < 0 = error "Non-negative numbers only"
	| otherwise = unwords $ map fb [1..n]

main :: IO ()
main = do
  print (fizzbuzz 1)
  print (fizzbuzz 7)
  print $ fizzbuzz 99
  print $ fizzbuzz 0
  print $ fizzbuzz (-2)