the SplStack is  simply a SplDoublyLinkedList with  an iteration mode IT_MODE_LIFO and IT_MODE_KEEP(PHP 5 >= 5.3.0, PHP 7, PHP 8)
    The SplStack class provides the main functionalities of a stack implemented using a doubly linked list by
    setting the iterator mode to SplDoublyLinkedList::IT_MODE_LIFO.
   
Örnek 1 SplStack example
<?php
$q = new SplStack();
$q[] = 1;
$q[] = 2;
$q[] = 3;
foreach ($q as $elem)  {
 echo $elem."\n";
}
?>Yukarıdaki örneğin çıktısı:
3 2 1
the SplStack is  simply a SplDoublyLinkedList with  an iteration mode IT_MODE_LIFO and IT_MODE_KEEP<?php
//SplStack Mode is LIFO (Last In First Out)
  
$q = new SplStack();
$q[] = 1;
$q[] = 2;
$q[] = 3;
$q->push(4);
$q->add(4,5);
$q->rewind();
while($q->valid()){
    echo $q->current(),"\n";
    $q->next();
}
?>
Output
5
4
3
2
1