首位插入：
<?php
$queue = array("orange", "banana");
array_unshift($queue, "apple", "raspberry");
print_r($queue);
?>
Array
(
[0] => apple
[1] => raspberry
[2] => orange
[3] => banana
) 尾部插入:
<?php
$stack = array("orange", "banana");
array_push($stack, "apple", "raspberry");
print_r($stack);
?>
Array
(
[0] => orange
[1] => banana
[2] => apple
[3] => raspberry
)