We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
  1. Practice
  2. Functional Programming
  3. Recursion
  4. Pascal's Triangle
  5. Discussions

Pascal's Triangle

  • strawstack + 2 comments

    UPDATE: Finally, figured out how to print a [[Char]] in the correct format with Haskell...

    -- PRINT with FORMAT    
two :: [Int] -> [String]
two m = map (show) m

three :: [[Int]] -> [[String]]
three m = map (two) m

main = do   
   m <- readLn :: IO Int
   --send (tri m) -- print tri to row m
   mapM_ (putStrLn . intercalate " " $) (three (tri m))

    Where (tri m) produces [["1"], ["1", "1"], ["1", "2", "1"], ["1", "3", "3", "1"]]

    • ende76 + 0 comments

      Thanks for this chain of posts. I was struggling through the same problems with how to properly output.
      Much longer than to solve the actual problem!

    • tury345 + 1 comment

      Achieved something similar here:

      putStr (unlines (map (\line -> unwords (map (\(x:[]) -> show x) line)) rows))

      where rows is [[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]

      • egoek + 1 comment

        I concocted this:

        mapM_ putStrLn (map (\x -> unwords (map show x)) result)

        where result is [[1], [1, 1], [1, 2, 1] ...] I'm sure I could get rid of the parenthesis. Any suggestions welcome.

        • twostepted + 0 comments

          Nice. Vscode extension 'Haskutil' recommended shorten slightly to this

            n <- readLn
  mapM_ (putStrLn . unwords . map show) $ tri n