Added 'Haskell/5.hs'

Haskell/5.hs

@@ -0,0 +1,31 @@
+import Data.Char (toUpper)
+
+headInt :: [Int] -> Int
+headInt (x:_) = x
+
+tailInt :: [Int] -> [Int]
+tailInt (x:xs) = xs
+
+nullInt :: [Int] -> Bool
+nullInt [] = True
+nullInt _  = False
+
+isSingleton :: [Int] -> Bool
+isSingleton [x] = True
+isSingleton  _  = False
+
+toUpperFirst :: [Char] -> [Char]
+toUpperFirst [] = []
+toUpperFirst (x:xs)  = toUpper x : xs
+
+isLetter :: Char -> Bool
+isLetter x = elem x ['A'..'z']
+
+compTest :: Char -> [Char]
+compTest x = [x..'z']
+
+mountain :: Int -> [Int]
+mountain x = [1..x] ++ [x - 1, x - 2 .. 1]
+
+divisors :: Int -> [Int]
+divisors n = [d | d <- [1..n], mod n d == 0]