Update Haskell

1 files changed, 21 insertions, 5 deletions

diff --git a/gcd.hs b/gcd.hs
index fe07fc0..b044c85 100644
--- a/gcd.hs
+++ b/gcd.hs
@@ -1,14 +1,30 @@
-import System.Environment(getArgs)
+{-
 
+Usage:
+
+  $ runhaskell gcd.hs 22 11
+  11
+
+or:
+
+  $ ghc gcd.hs -o gcd-hs
+  $ ./gcd-hs 11 22 121
+  11
+
+-}
+import System.Environment (getArgs)
+
+gcd2 :: Integer -> Integer -> Integer
 gcd2 a 0 = a
 gcd2 a b = gcd2 b (a `rem` b)
 
-gcdn n = foldl1 gcd2 n
+gcdn :: [Integer] -> Integer
+gcdn = foldl1 gcd2
 
 str2int :: String -> Integer
 str2int = read
 
+main :: IO ()
 main = do
-    a <- getArgs
-    print (gcdn (map str2int a))
-
+  a <- getArgs
+  print $ gcdn (map str2int a)