import IO
import Char

main =  do hdl <- openFile  "/tmp/foo.txt" WriteMode
	   hPutChar hdl (chr 66)
	   hPutChar hdl ("ABCD" !! 0)
	   hClose hdl
	   hdl <- openFile  "/tmp/foo.txt" ReadMode
	   x <- hGetContents hdl
	   putStr x