Given a year, report if it is a leap year.
The tricky thing here is that a leap year in the Gregorian calendar occurs:
on every year that is evenly divisible by 4 except every year that is evenly divisible by 100 unless the year is also evenly divisible by 400
For example, 1997 is not a leap year, but 1996 is. 1900 is not a leap year, but 2000 is.
If your language provides a method in the standard library that does this look-up, pretend it doesn't exist and implement it yourself.
Though our exercise adopts some very simple rules, there is more to learn!
For a delightful, four minute explanation of the whole leap year phenomenon, go watch this youtube video.
JavaRanch Cattle Drive, exercise 3 http://www.javaranch.com/leap.jsp
It's possible to submit an incomplete solution so you can see how others have completed the exercise.
module Test.Main where import Prelude import Effect (Effect) import Test.Unit (TestSuite, suite, test) import Test.Unit.Main (runTest) import Test.Unit.Assert as Assert import Leap as Leap main :: Effect Unit main = runTest suites suites :: TestSuite suites = do suite "Leap.isLeapYear" do test "leap year" do Assert.equal true $ Leap.isLeapYear 1996 test "non-leap year" do Assert.equal false $ Leap.isLeapYear 1997 test "non-leap even year" do Assert.equal false $ Leap.isLeapYear 1998 test "century" do Assert.equal false $ Leap.isLeapYear 1900 test "second century" do Assert.equal false $ Leap.isLeapYear 1800 test "fourth century" do Assert.equal true $ Leap.isLeapYear 2400 test "y2k" do Assert.equal true $ Leap.isLeapYear 2000
module Leap where import Prelude isLeapYear :: Int -> Boolean isLeapYear n = fourHundred || (four && (not hundred)) where fourHundred = n `mod` 400 == 0 hundred = n `mod` 100 == 0 four = n `mod` 4 == 0
A huge amount can be learned from reading other people’s code. This is why we wanted to give exercism users the option of making their solutions public.
Here are some questions to help you reflect on this solution and learn the most from it.