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.
Follow the setup instructions for Crystal here:
More help installing can be found here:
Execute the tests with:
$ crystal spec
In each test suite all but the first test have been skipped.
Once you get a test passing, you can unskip the next one by changing
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.
require "spec" require "../src/*" struct Time def leap_year? raise "That's too easy! Implement this method in your own way!" end end describe "Leap" do describe "#leap?" do it "marks 1996 as a leap year" do Year.leap?(1996).should be_true end pending "marks 1997 not as a leap year" do Year.leap?(1997).should be_false end pending "marks 1998 not as a leap year" do Year.leap?(1998).should be_false end pending "marks 1900 not as a leap year" do Year.leap?(1900).should be_false end pending "marks 2400 as a leap year" do Year.leap?(2400).should be_true end pending "marks 2000 as a leap year" do Year.leap?(2000).should be_true end end end
module Year extend self def leap?(n : Int) : Bool n.divisible_by?(4) && !n.divisible_by?(100) || n.divisible_by?(400) end end
A huge amount can be learnt 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.