佇列

佇列是先進先出的資料結構，先塞進來的資料就必須先取出。

class Queue{
private $head=0,$tail=0;
private $max=100;
private $data=array();
private $error;

public function pop(){
if($this->head != $this->tail){
$this->head++;
if($this->head >$this->max){
$this->head = $this->head -$this->max - 1;
}
$data = $this->data[$this->head];
unset($this->data[$this->head]);
return $data;
}
}

public function push($data){
$original=$this->tail;
$this->tail++;
if($this->tail >$this->max){
$this->tail = $this->tail - $this->max -1;
}

if($this->tail == $this->head){
$this->error='佇列已滿';
$this->tail=$original;
return false;
}else{
$this->data[$this->tail]=$data;
return true;
}
}

public function showQueue(){
foreach($this->data as $key=>$value){
echo $key.'=>'.$value."\n";
}
}

}

$queue=new Queue();

for($i=0;$i<=2000;$i++){
$queue->push($i);
}

for($i=0;$i<39;$i++){
$queue->pop();
}

for($i=0;$i<100;$i++){
$queue->push($i);
}


$queue->showQueue();


程式碼解說:
Queue::pop() 取出資料
Queue::push() 塞進資料
Queue::showQueue() 列出佇列內的所有資料