$a = new SplDoublyLinkedList;
$arr=[1,2,3,4,5,6,7,8,9];
for($i=0;$i<count($arr);$i++){
$a->add($i,$arr[$i]);
}
echo "SplDoublyLinkedList array last/top value " . $a->top() ." \n";
echo "SplDoublyLinkedList array first/top value " . $a->bottom() . " \n\n";
print_r($a);
//Another Example
$spl = new SplDoublyLinkedList;
$spl->push(11);
$spl->push(2);
$spl->push(3);
$spl->push(8);
$spl->push(5);
//array last value
echo $spl->top();
echo PHP_EOL;
//Array first value
echo $spl->bottom();
echo PHP_EOL;
print_r($spl);