note 58508 deleted from function.abs by derick
| From: | derick@php.net | Date: | Thu, 27 Aug 2009 08:02:07 +0000 |
| Subject: | note 58508 deleted from function.abs by derick | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-159918@lists.php.net to get a copy of this message | ||
Note Submitter: concordia at game dot xakep dot org
----
Sometimes you may want to do the opposite of abs(): turn a positive number into a negative.
<?php
function turn_neg ($num) {
return $num - $num * 2;
}
?>
But this can create errors when you put a negative number inside...
turn_neg (-2) returns 6.
<?php
turn_neg (-2); // 6.
?>
The solution is to make another function to determine if the number is negative or not.
<?php
function is_neg ($num) {
return $num < 0;
}
function turn_neg ($num) {
if (is_neg ($num)) {
return $num - $num * 2;
} else {
return abs ($num);
}
}
turn_neg (2); // -2
turn_neg (-2); // 2
?>
Or, if the number is not negative, you could also return false.