check :: String -> String -> Char -> (Bool, String)
-- check whether a single char is in the mystery word
check word display c
  = (c `elem` word, [if x==c
          then c
          else y | (x,y) <- zip word display])
check :: String -> String -> Char -> (Bool, String)
check word display c
  = (c `elem` word, [if x==c
          then c
          else y | (x,y) <- zip word display])
check word display c
  = (c `elem` word, [if x==c
          then c
          else y | (x,y) <- zip word display])