Lab0.hs

module Lab0 where

import Data.List
import Data.Char
import System.Random
import Test.QuickCheck

prime :: Integer -> Bool
prime n = n > 1 && all (\ x -> rem n x /= 0) xs
  where xs = takeWhile (\ y -> y^2 <= n) primes

primes :: [Integer]
primes = 2 : filter prime [3..] 

infix 1 --> 

(-->) :: Bool -> Bool -> Bool
p --> q = (not p) || q

for_all :: [a] -> (a -> Bool) -> Bool
for_all = flip all

probs :: Int -> IO [Float]
probs 0 = return []
probs n = do
    p <- getStdRandom random
    ps <- probs (n-1)
    return (p:ps)

reversibleStream :: [Integer]
reversibleStream = undefined

reversal :: Integer -> Integer
reversal = read . reverse . show

rot13 :: [Char] -> [Char]
rot13 = undefined

consecutive101Prime :: Integer
consecutive101Prime = undefined

euler9 :: Integer
euler9 = undefined

euler10 :: Integer
euler10 = undefined

euler49 :: Integer
euler49 = undefined

-- #################################################

doubleMe :: Num a => a -> a
doubleMe x = x+x

doubleUs :: Integer -> Integer -> Integer
doubleUs a b = doubleMe a + doubleMe b

doubleSmallNumber :: (Ord a, Num a) => a -> a
doubleSmallNumber a = if a < 100
                        then a + a 
                        else a