Sum digits of an integer: Difference between revisions

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 <pre>30</pre>
 In terms of unfoldr:
 <lang haskell>import Data.List (unfoldr)
 import Data.Tuple (swap)
+----------------- SUM DIGITS OF AN INTEGER ---------------
 baseDigitSum :: Int -> Int -> Int
-baseDigitSum base n =
+baseDigitSum base = sum . unfoldr go
-  sum $
+  where
-  unfoldr
+    go x
+      | 0 < x = (Just . swap) $ quotRem x base
-    (\x ->
-        if 0 < x
+      | otherwise = Nothing
-          then Just $ swap $ quotRem x base
-          else Nothing)
-    n
+-------------------------- TESTS -------------------------
 main :: IO ()
 main =
   mapM_
     print
-    [ baseDigitSum <$> [2, 8, 10, 16] <*> [255]
+    [ baseDigitSum <$> [2, 8, 10, 16] <*> [255],
-    , baseDigitSum <$> [10] <*> [1, 1234]
+      baseDigitSum <$> [10] <*> [1, 1234],
-    , baseDigitSum <$> [16] <*> [0xfe, 0xf0e]
+      baseDigitSum <$> [16] <*> [0xfe, 0xf0e]
     ]</lang>
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