plusone x = x + 1
lastone = head . reverse
prefix = reverse . tail . reverse
mymap f l = [ f x | x <- l] myfilter f l = [ x | x <- l, f x] absolute x | x < 0 = -x | x>= 0 = x
myand :: Bool -> Bool -> Bool
myand True False = False
myand True True = True
myand False False = False
myand False True = False
myand2 True True = True
myand2 x y = False
hd (x:xs) = x
tl (x:xs) = xs
firstOfThree [x,y,z] = x
plus :: Int -> Int -> Int
plus x y = if x == 0 then y else 1 + (plus (x-1) y)
len [] = 0
len (x:xs) = 1 + (len xs)
len2 [] = 0
len2 (x:xs) = 1 + z where z = len2 xs
choose x y z = if x then y else z
difference x y = x - y
k x y = x
sort :: Ord a => [a] -> [a]
sort = foldr insert []
insert :: Ord a => a -> [a] -> [a]
insert x [] = [x]
insert x (y:ys)
 | x <= y = x:y:ys | otherwise = y:insert x ys --