Exercism v3 launches on Sept 1st 2021. Learn more! ðŸš€ðŸš€ðŸš€

Instructions

Test suite

Solution

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.

The DateTime class in F# provides a built-in IsLeapYear method which you should pretend doesn't exist for the purposes of implementing this exercise.

To run the tests, run the command `dotnet test`

from within the exercise directory.

For more detailed information about the F# track, including how to get help if you're having trouble, please visit the exercism.io F# language page.

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.

```
// This file was auto-generated based on version 1.4.0 of the canonical data.
module LeapTest
open FsUnit.Xunit
open Xunit
open Leap
[<Fact>]
let ``Year not divisible by 4: common year`` () =
leapYear 2015 |> should equal false
[<Fact(Skip = "Remove to run test")>]
let ``Year divisible by 4, not divisible by 100: leap year`` () =
leapYear 1996 |> should equal true
[<Fact(Skip = "Remove to run test")>]
let ``Year divisible by 100, not divisible by 400: common year`` () =
leapYear 2100 |> should equal false
[<Fact(Skip = "Remove to run test")>]
let ``Year divisible by 400: leap year`` () =
leapYear 2000 |> should equal true
[<Fact(Skip = "Remove to run test")>]
let ``Year divisible by 200, not divisible by 400: common year`` () =
leapYear 1800 |> should equal false
```

```
ï»¿module Leap
let leapYear (year: int): bool =
year % 4 = 0 && (year % 100 <> 0 || year % 400 = 0)
```

A huge amount can be learned from reading other peopleâ€™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.

- What compromises have been made?
- Are there new concepts here that you could read more about to improve your understanding?

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