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 '
';?>?