Even Odd in Haskell

Published on 28 April 2022 (Updated: 05 February 2023)

Even Odd in Haskell

Welcome to the Even Odd in Haskell page! Here, you’ll find the source code for this program as well as a description of how the program works.

Current Solution

module Main where

import System.Environment
import Text.Read

data EvenOdd = Even | Odd deriving (Show)

isEvenOdd :: Int -> EvenOdd
isEvenOdd x
  | x `mod` 2 == 0 = Even
  | otherwise  = Odd

headMaybe :: [a] -> Maybe a
headMaybe []     = Nothing
headMaybe (x:xs) = Just x

main :: IO ()
main = do
  args <- getArgs
  let x = headMaybe args
  case x >>= readMaybe of
    Nothing -> putStrLn "Usage: please input a number"
    Just x  -> putStrLn $ show $ isEvenOdd x

Even Odd in Haskell was written by:

If you see anything you’d like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of Nov 16 2018 11:15:37. The solution was first committed on Nov 16 2018 01:28:55. As a result, documentation below may be outdated.

How to Implement the Solution

No ‘How to Implement the Solution’ section available. Please consider contributing.

How to Run the Solution

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