A simple program in Haskell written while reading "Programming in Haskell". It prints a diagonal line of +es.

plusrow.hs

makeString :: Char -> Int -> String
makeString _ 0 = []
makeString c i = c : (makeString c (i - 1))

putStringsLn :: [String] -> IO ()
putStringsLn [] = return ()
putStringsLn (s : ss) = do
    putStrLn s
    putStringsLn ss
    
main = do
    putStringsLn ss
    where
        ss = [(makeString ' ' i) ++ "+" | i <- [1..10]]