JuniorTheoryCommon

What does the program print?

PHP

<?php

$words = ['pear', 'fig', 'banana'];
usort($words, fn($a, $b) => strlen($a) <=> strlen($b));
echo implode(' ', $words), "\n";

fig pear banana

Expecting usort to return a sorted copy and leave $words alone: it receives the array by reference, sorts it in place and returns true.
Expecting $a <=> $b to sort from largest to smallest: it is negative when $a is smaller, which puts $a first; descending needs $b <=> $a.

How would you change the comparison function to sort the words from longest to shortest?
What would $sorted = usort($words, …) put into $sorted?

JuniorTheoryCommon

PHP

<?php

$words = ['pear', 'fig', 'banana'];
usort($words, fn($a, $b) => strlen($a) <=> strlen($b));
echo implode(' ', $words), "\n";

fig pear banana

Expecting usort to return a sorted copy and leave $words alone: it receives the array by reference, sorts it in place and returns true.
Expecting $a <=> $b to sort from largest to smallest: it is negative when $a is smaller, which puts $a first; descending needs $b <=> $a.

How would you change the comparison function to sort the words from longest to shortest?
What would $sorted = usort($words, …) put into $sorted?