module Foo.Bar where

import Control.Monad.State
import Test.QuickCheck

countAtEven [] = return ()
countAtEven (x:xs) = do when (even 2) $
                          modify (\s -> s + 1)
                        countAtOdd xs

countAtOdd [] = return ()
countAtOdd (x:xs) = do when (odd 2) $
                         modify (\s -> s + 1)
                       countAtEven xs


count l = runState (countAtOdd l) 0

rotate n l = take (length l) . drop n . cycle $ l

t = quickCheck (\l -> (count l) == (count $ rotate 2 (l :: [Int])))