class deque

{

public $queue  = array();

public $length = 0;

public function frontAdd($node){

array_unshift($this->queue,$node);

$this->countqueue();

}

public function frontRemove(){

$node = array_shift($this->queue);

$this->countqueue();

return $node;

}

public function rearAdd($node){

array_push($this->queue,$node);

$this->countqueue();

}

public function rearRemove(){

$node = array_pop($this->queue);

$this->countqueue();

return $node;

}

public function countqueue(){

$this->length = count($this->queue);

}

}

$fruit = new deque();

echo $fruit -> length;

$fruit -> frontAdd("Apple");

$fruit -> rearAdd("Watermelon");

echo '

';

print_r($fruit);

echo '

?>

结果

0

deque Object

(

[queue] => Array

(

[0] => Apple

[1] => Watermelon

)

[length] => 2

)