note 74308 added to language.expressions

It is worthy to mention that: $n = 3; $n * --$n WILL RETURN 4 instead of 6. It can be a hard to spot "error", because in our human thought process this really isn't an error at all! But you have to remember that PHP (as it is with many other high-level languages) evaluates its statements RIGHT-TO-LEFT, and therefore "--$n" comes BEFORE multiplying, so - in the end - it's really "2 * 2", not "3 * 2". It is also worthy to mention that the same behavior will change: $n = 3; $n * $n++ from 3 * 3 into 3 * 4. Post- operations operate on a variable after it has been 'checked', but it doesn't necessarily state that it should happen AFTER an evaluation is over (on the contrary, as a matter of fact). So, if you ever find yourself on a 'wild goose chase' for a bug in that "impossible-to-break, so-very-simple" piece of code that uses pre-/post-'s, remember this post. :) (just thought I'd check it out - turns out I was right :P) ---- Server IP: 69.147.83.197 Probable Submitter: 85.221.134.122 ---- Manual Page -- http://www.php.net/manual/en/language.expressions.php Edit -- https://master.php.net/note/edit/74308 Del: integrated -- https://master.php.net/note/delete/74308/integrated Del: useless -- https://master.php.net/note/delete/74308/useless Del: bad code -- https://master.php.net/note/delete/74308/bad+code Del: spam -- https://master.php.net/note/delete/74308/spam Del: non-english -- https://master.php.net/note/delete/74308/non-english Del: in docs -- https://master.php.net/note/delete/74308/in+docs Del: other reasons-- https://master.php.net/note/delete/74308 Reject -- https://master.php.net/note/reject/74308 Search -- https://master.php.net/manage/user-notes.php