unnecessary variable in the example of for loop

From manual page: https://php.net/control-structures.for

 /* example 4 */
for ($i = 1, $j = 0; $i <= 10; $j += $i, print $i, $i++);

This example 4 is clearly different and problematic compared to the other three examples. It demonstrates that in PHP, there can be multiple notations that yield the same output in a for loop. However, unlike the other examples, only example 4 includes the unnecessary variable $j. While the result remains the same, it is evident that adding $j is an unnecessary modification to this particular example.

According to https://bugs.php.net/bug.php?id=36877, https://github.com/php/doc-en/commit/29cf2d82f2b9a45e28e4ac0fdc672c9ec36b4c33, I investigated the origin of $j and discovered that it resulted from a documentation fix implemented in 2006. The report states:

The C-like clause for expr1 in
for ($i=0, $n=10; ...)
is accepted but not documented.
The corresponding C-like clause
$i=0, $j=1; outside a for is flagged as an error.

In my opinion, this modification was inappropriate. I believe it's more appropriate for the manual to provide explicit and clear explanations rather than relying on unnecessary variables for implicit demonstrations.

Start with the PHP manual page for control structures and inspect example 4 alongside the other for-loop examples. Review the linked bug report and historical commit for context; done means removing the unnecessary $j variable while preserving the example's intended output and explanation.