Files
book-exercises/Haskell-book/13/Cipher.hs

17 lines
402 B
Haskell

module Cipher where
import Data.Char
import Data.List
vigenere :: String -> String
vigenere = f (cycle [0, 11, 11, 24])
where f _ [] = []
f ys (' ':xs) = ' ' : (f ys xs)
f (y:ys) (x:xs) = (decode (x, y)) : (f ys xs)
where decode (x, y) = chr ((mod ((ord x) - 65 + y) 26) + 65)
main :: IO ()
main = do
i <- getLine
putStrLn $ vigenere i