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Diffstat (limited to 'Haskell-book/14/addition/Addition.hs')
| -rw-r--r-- | Haskell-book/14/addition/Addition.hs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/Haskell-book/14/addition/Addition.hs b/Haskell-book/14/addition/Addition.hs new file mode 100644 index 0000000..474eecd --- /dev/null +++ b/Haskell-book/14/addition/Addition.hs @@ -0,0 +1,35 @@ +module Addition where + +import Test.Hspec +import Test.QuickCheck + +dividedBy :: Integral a => a -> a -> (a, a) +dividedBy num denom = go num denom 0 + where go n d count + | n < d = (count, n) + | otherwise = go (n - d) d (count + 1) + +multiplyBy :: (Ord a, Eq a, Num a) => a -> a -> a +multiplyBy a b + | a == 0 || b == 0 = 0 + | a > 0 && b > 0 = multiplyBy' a b + | a < 0 && b < 0 = multiplyBy' (-a) (-b) + | a < 0 && b > 0 = -(multiplyBy' (-a) b) + | a > 0 && b < 0 = -(multiplyBy' a (-b)) + where multiplyBy' c 1 = c + multiplyBy' c d = c + (multiplyBy c (d - 1)) + +main :: IO () +main = hspec $ do + describe "Addition" $ do + it "15 divided by 3 is 5" $ do + dividedBy 15 3 `shouldBe` (5, 0) + it "22 divided by 5 is 4 remainder 2" $ do + dividedBy 22 5 `shouldBe` (4, 2) + it "x + 1 is always greater than x" $ do + property $ \x -> x + 1 > (x :: Int) + describe "Multiplication" $ do + it "15 multiplied by 3 is 45" $ do + multiplyBy 15 3 `shouldBe` 45 + it "22 multiplied by 5 is 110" $ do + multiplyBy 22 5 `shouldBe` 110
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