PHP two-way queue, double-ended queue code

queue=$queue; } } /** * 获取第一个元素 */ public function front() { return reset($this->queue); } /** * 获取最后一个元素 */ public function back() { return end($this->queue); } /** * 判断是否为空 */ public function is_empty() { return empty($this->queue); } /** * 队列大小 */ public function size() { return count($this->queue); } /** * 插入到尾 */ public function push_back($val) { array_push($this->queue,$val); } /** * 插入到头 */ public function push_front($val) { array_unshift($this->queue,$val); } /** * 移除最后一个元素 */ public function pop_back() { return array_pop($this->queue); } /** * 移除第一个元素 */ public function pop_front() { return array_shift($this->queue); } /** * 清空队列 */ public function clear() { $this->queue=array(); } } //初始化一个双向队列 $deque=new Deque(array(1,2,3,4,5)); echo $deque->size().PHP_EOL; echo $deque->is_empty().PHP_EOL; echo $deque->front().PHP_EOL; echo $deque->back().PHP_EOL; echo PHP_EOL; //弹出元素测试 echo $deque->pop_back().PHP_EOL; echo $deque->pop_front().PHP_EOL; echo $deque->size().PHP_EOL; echo PHP_EOL; $deque->push_back('a').PHP_EOL; $deque->push_front(0).PHP_EOL; echo PHP_EOL; //插入测试 echo $deque->front().PHP_EOL; echo $deque->back().PHP_EOL; echo $deque->size().PHP_EOL; echo PHP_EOL; //清空测试 $deque->clear(); echo $deque->is_empty();