import Data.Char


-- 1 zadacha
countDigits :: Int -> Int
countDigits n
    | n < 10    = 1
    | otherwise = 1 + (countDigits(n `div` 10 ))

countDigitsIter :: Int -> Int
countDigitsIter n = helper n 0
     where
         helper 0 cnt = cnt
         helper number cnt = helper (number `div` 10)(cnt + 1)


-- 2 zadacha

sumDigits :: Int -> Int
sumDigits number
    | number == 0 = 0
    | otherwise   = 0 + (sumDigits(number `mod` 10))

sumDigitsIter :: Int -> Int
sumDigitsIter n = helper n 0
     where
         helper 0 sum      = sum
         helper number sum = helper (number `div` 10)(sum + (number `mod` 10))

-- 3 zadacha

countOccurences :: Int -> Int -> Int
countOccurences n digit
        | n `mod` 10 == digit = 1 + countOccurences(n `div` 10)
        | otherwise            = countOccurences(n `div` 10)

countOccurencesIter :: Int -> Int -> Int
countOccurencesIter number digit = helper number digit 0
     where
         helper number digit cnt
            | number == digit = helper (number `div` 10)(digit)(cnt + 1)
            | otherwise       = helper (number `div` 10)(digit)(cnt)





main :: IO ()
main = do
   -- print (countDigits 49128)
    -- print (countDigitsIter 128)
    -- print (sumDigitsIter 123)
print(countOccurences 1233 3)
print(countOccurencesIter 1233 3)