lab3

import Data.Char

vocaleCuv :: String -> Int
vocaleCuv "" = 0
vocaleCuv (h:t)
    | elem h "aeiouAEIOU"   = 1 + t'
    | otherwise = t'
    where t' = vocaleCuv t

nrVocale :: [String] -> Int
nrVocale [] = 0
nrVocale (h:t)
    | h == reverse h    = vocaleCuv h + t'
    | otherwise = t'
    where t' = nrVocale t

f :: Int -> [Int] -> [Int]
f val [] = []
f val (h:t)
    | h `mod` 2 == 0    = h:val:t'
    | otherwise         = h:t'
    where t' = f val t

divizori :: Int -> [Int]
divizori n = [n `div` x| x <- reverse [1..n], n `mod` x == 0]

listadiv :: [Int] -> [[Int]]
listadiv lista = [divizori k| k <- lista]


inIntervalComp::Int -> Int -> [Int] -> [Int]
inIntervalComp stg drp lis = [k | k <- lis, k >= stg, k <= drp]


inIntervalRec :: Int -> Int -> [Int] -> [Int]
inIntervalRec a b [] = []
inIntervalRec a b (h:t)
    | a <= h && h <= b   = h : t'
    | otherwise     = t'
    where t' = inIntervalRec a b t

pozitiveComp :: [Int] -> Int
pozitiveComp l = length [k | k <- l, k > 0]

pozitiveRec :: [Int] -> Int
pozitiveRec [] = 0
pozitiveRec (h:t)
    | h > 0 = 1 + t'
    | otherwise = t'
    where t' = pozitiveRec t
    
pozitiiImpareRec :: [Int] -> Int -> [Int]
pozitiiImpareRec [] a = []
pozitiiImpareRec (h:t) a
    | odd h    = a : t'
    | otherwise = t'
    where t' = pozitiiImpareRec t (a + 1)

numere = [0..]
pozitiiImpareComp :: [Int] -> [Int]
pozitiiImpareComp lista = [i | (i, x) <- zip numere lista, odd x]

multDigitsRec :: String -> Int
multDigitsRec "" = 1
multDigitsRec (h:t)
    | isDigit h = (digitToInt h) * t'
    | otherwise = t'
    where t' = multDigitsRec t

multDigitsComp :: String -> Int
multDigitsComp sir = product [digitToInt k| k <- sir, isDigit k]