What's the difference between ++$i and $i++ in PHP?

In PHP, "++$i" is the pre-increment operator and "$i++" is the post-increment operator. The difference between the two is the order in which the operation is performed.

With the pre-increment operator (++$i), the value of the variable is incremented before it is used in the statement.

With the post-increment operator ($i++), the value of the variable is incremented after it is used in the statement.

For example:

<?php

$i = 5;
echo ++$i; // returns 6

echo "\r\n";

$i = 5;
echo $i++; // returns 5

In the first example, the variable $i is incremented before it is printed, so the output is 6. In the second example, the variable is printed first and then incremented, so the output is 5.