Haskell学习笔记IO

Haskell学习笔记--IO

（是IO不是OI

下周考试，赶紧冲刺

data IO a

A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a.

return :: a -> IO a 

putChar :: Char -> IO ()

putStr  :: String -> IO () 打完不换行

putStrLn :: String -> IO() 打完换行

getChar :: IO Char 

getLine :: IO String