move to IO folder

Author: EpsilonX

arg-test.hs renamed to IO/arg-test.hs

@@ -0,0 +1,22 @@
+import System.Random
+import Control.Monad(when)
+
+main = do
+    gen <- getStdGen
+    askForNumber gen
+
+askForNumber :: StdGen -> IO ()
+askForNumber gen = do
+    let (randNumber, newGen) = randomR (1,10) gen :: (Int, StdGen)
+    putStr "Which number in the range from 1 to 10 am I thinking of?"
+    numberString <- getLine
+    when (not $ null numberString) $ do
+        let number = read numberString
+        if randNumber == number
+            then putStrLn "You are correct!"
+            else putStrLn $ "Sorry, it was " ++ show randNumber
+        askForNumber newGen
+        {-- another way:
+        newStdGen
+        main
+        --}

IO/askForNumber.hs

@@ -0,0 +1,11 @@
+import System.Environment
+import qualified Data.ByteString.Lazy as B
+
+main = do
+    (filename1:filename2:_) <- getArgs
+    copyFile filename1 filename2
+
+copyFile :: FilePath -> FilePath -> IO ()
+copyFile source dest = do
+    contents <- B.readFile source
+    B.writeFile dest contents

IO/copyFile.hs

@@ -0,0 +1,31 @@
+import System.Random
+
+threeCoins :: StdGen -> (Bool, Bool, Bool)
+threeCoins gen =
+    let (firstCoin, newGen) = random gen
+        (secondCoin, newGen') = random newGen
+        (thirdCoin, newGen'') = random newGen'
+    in (firstCoin, secondCoin, thirdCoin)
+
+randoms' :: (RandomGen g, Random a) => g -> [a]
+randoms' gen = let (value, newGen) = random gen in value:randoms' newGen
+
+finiteRandoms :: (RandomGen g, Random a, Num n,Eq n) => n -> g -> ([a],g)
+finiteRandoms 0 gen = ([],gen)
+finiteRandoms n gen =
+    let (value, newGen) = random gen
+        (restOfList, finalGen) = finiteRandoms (n-1) newGen
+    in  (value:restOfList, finalGen)
+
+main = do
+    gen <- getStdGen
+    {--
+    let randomChars = randomRs ('a','z') gen
+        (first20,rest) = splitAt 20 randomChars
+        (second20,_) = splitAt 20 rest
+    putStrLn first20
+    putStrLn second20
+    --}
+    putStrLn $ take 20 (randomRs ('a','z') gen)
+    gen' <- newStdGen
+    putStr $ take 20 (randomRs ('a','z') gen')