Add remaining haskell book exercises

1 files changed, 29 insertions, 0 deletions

diff --git a/Haskell-book/23/FizzBuzz.hs b/Haskell-book/23/FizzBuzz.hs
new file mode 100644
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+++ b/Haskell-book/23/FizzBuzz.hs
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+module FizzBuzz where
+
+import Control.Monad
+import Control.Monad.Trans.State
+
+fizzBuzz :: Integer -> String
+fizzBuzz n
+  | n `mod` 15 == 0 = "FizzBuzz"
+  | n `mod` 5 == 0 = "Buzz"
+  | n `mod` 3 == 0 = "Fizz"
+  | otherwise = show n
+
+fizzbuzzList :: [Integer] -> [String]
+fizzbuzzList list = execState (mapM_ addResult list) []
+
+addResult :: Integer -> State [String] ()
+addResult n = do
+    xs <- get
+    let result = fizzBuzz n
+    put (result : xs)
+
+fizzbuzzFromTo :: Integer -> Integer -> [String]
+fizzbuzzFromTo from to = execState (mapM_ addResult (genList from [])) []
+    where genList from soFar
+            | from > to = soFar
+            | otherwise = genList (from + 1) (from : soFar)
+
+main :: IO ()
+main = mapM_ putStrLn $ fizzbuzzFromTo 1 100