php实现队列

<?php

class node{
public $value;
public function __construct($value){
$this->value = $value;
}
}

class queue{

public $head;
public $last;
public $queuelist;
public $size = 0;

//出队列
public function dequeue(){
if(0 == $this->size){
return ;
exit(‘the queue is empty‘);
}
$current = $this->head;
array_shift($this->queuelist);
$this->head = current($this->queuelist);
$this->size--;
return $current;
}

//入队列
public function enqueue($value){

$node = new node($value);
$this->queuelist[] = $node;
if( 0 == $this->size){
$this->head = $node;
}
$this->last = $node ;
$this->size++;

}

public function size(){
return $this->size;
}

}

$queue = new queue();

for($i=0;$i<10;$i++){
$queue->enqueue($i);
}

while($value = $queue->dequeue()){
var_dump($value);
}