4d47's solution

to Leap in the PHP Track

Published at Jul 13 2018 · 0 comments
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.

Notes

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.

Running the tests

1. Go to the root of your PHP exercise directory, which is `<EXERCISM_WORKSPACE>/php`. To find the Exercism workspace run

`````` % exercism debug | grep Workspace
``````
2. Get PHPUnit if you don't have it already.

`````` % wget --no-check-certificate https://phar.phpunit.de/phpunit.phar
% chmod +x phpunit.phar
``````
3. Execute the tests:

`````` % ./phpunit.phar leap/leap_test.php
``````

Source

JavaRanch Cattle Drive, exercise 3 http://www.javaranch.com/leap.jsp

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

leap_test.php

``````<?php

require "leap.php";

class YearTest extends PHPUnit\Framework\TestCase
{
public function testLeapYear()
{
\$this->assertTrue(isLeap(1996));
}

public function testNonLeapYear()
{
\$this->assertFalse(isLeap(1997));
}

public function testNonLeapEvenYear()
{
\$this->assertFalse(isLeap(1998));
}

public function testCentury()
{
\$this->assertFalse(isLeap(1900));
}

public function testFourthCentury()
{
\$this->assertTrue(isLeap(2400));
}
}``````
``````<?php

function divides(\$divisor, \$dividend) {
return \$dividend % \$divisor === 0;
}

function isLeap(\$year)
{
return divides(4, \$year) && (!divides(100, \$year) || divides(400, \$year));
}``````