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Multiplication tables: Difference between revisions

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Multiplication tables (view source)

Revision as of 18:59, 19 December 2016

383 bytes removed ,  7 years ago
m
→‎{{header|Haskell}}: (Layout)
(→‎{{header|Haskell}}: Switched core type from [Int] to Maybe Int)
Line 2,242:
 
=={{header|Haskell}}==
<lang haskell>importmultTable Control.Monad:: Int -> [[Maybe Int]]
multTable n = ▼
import Text.Printf
(\x ->
 
Just x :▼
main = do
fmt Nothing = pad:▼
putStrLn $ " x" ++ concatMap fmt [1..12]
((\y ->
zipWithM_ f [1..12] $ iterate (" " ++) ""
if sy =< show nx▼
where f n s = putStrLn $ fmt n ++ s ++ concatMap (fmt . (*n)) [n..12]
fmt n = printf "%4d" (nthen :: Int)</lang>Nothing
(\y -> if y < x then Nothing else Just (x * y)) <$>▼
 
where range)) = [1..n]<$>▼
 
<$> range▼
Or, making do without imports beyond the Prelude, and separating data from formatting:
where▼
 
range = [1 .. n]
<lang Haskell>multTable :: Int -> [[Maybe Int]]
▲multTable n =
(\x -> Just x : Nothing : (
▲ (\y -> if y < x then Nothing else Just (x * y))
<$> range))
▲ <$> range
▲ where range = [1..n]
▲
 
tableString :: [[Maybe Int]] -> String
tableString tbl = unlines $ (concat . (fmt <$>)) <$> tbl
where
unlines $ (concat . (fmt <$>)) <$> tbl
pad = " "
fmt Nothing = pad
fmt (Just n) = drop (length s) (pad ++ s)▼
where
pad s = " show "n
▲ fmt Nothing = pad
▲ fmt (Just n) = drop (length s) (pad ++ s)
▲ where
▲ s = show n
 
main :: IO ()
Hout
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