If you don't mind destroying the array (or a temp copy of it) you can do:
$stack = array("orange", "banana", "apple", "raspberry");
while ($fruit = array_pop($stack)){
echo $fruit . "\n<br>";
}
produces:
raspberry
apple
banana
orange
I think this solution reads cleaner than fiddling with an index and you are less likely to introduce index handling mistakes, but the problem with it is that your code will likely take slightly longer to run if you have to create a temporary copy of the array first. Fiddling with an index is likely to run faster, and it may also come in handy if you actually need to reference the index, as in:
$stack = array("orange", "banana", "apple", "raspberry");
$index = count($stack) - 1;
while($index > -1){
echo $stack[$index] ." is in position ". $index . "\n<br>";
$index--;
}
But as you can see, you have to be very careful with the index...