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.

To compile and run the tests, just run the following in your exercise directory:

```
$ nim c -r leap_test.nim
```

Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/nim/leap`

directory.

You can find your Exercism workspace by running `exercism debug`

and looking for the line that starts with `Exercises Directory`

.

For more detailed information about running tests, code style and linting, please see the help 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.

```
import unittest
from leap import isLeapYear
suite "Leap":
test "year not divisible by 4: common year":
check isLeapYear(2015) == false
test "year divisible by 4, not divisible by 100: leap year":
check isLeapYear(1996) == true
test "year divisible by 100, not divisible by 400: common year":
check isLeapYear(2100) == false
test "year divisible by 400: leap year":
check isLeapYear(2000) == true
```

```
proc isLeapYear*(year: int): bool =
return year mod 4 == 0 and year mod 100 != 0 or year mod 400 == 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.

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

Level up your programming skills with 3,113 exercises across 52 languages, and insightful discussion with our volunteer team of welcoming mentors.
Exercism is
**100% free forever**.

## Community comments