介绍队列是一个有序队列，可以用数组或者链表来实现。它遵循先进先出的原则，即队列中先存入的数据必须先取出，后存入的数据必须后取出。数组模拟队列1。需要一个最大容量maxSize.2。定义两个变量front和rear，front会随着数据的输出而变化，rear会随着数据的输入而变化。将数据存入队列1.将尾指针向后移动：$rear+1.将$rear==$front，队列为空；2、如果尾指针rear小于队列的最大下标maxSize-1，则将数据存入rear指向的数组元素中。rear==maxSize-1，队列已满。代码实现：maxSize=$maxSize;$this->front=-1;$this->rear=-1;$this->arr=[];}//显示队列数据publicfunctionshowQueue(){for($i=$this->front+1;$i<=$this->rear;$i++){echo$this->arr[$i].'';}}//插入数据publicfunctionpush($value){if($this->isFull()){thrownew\Exception('队列已满');}$this->rear++;$this->arr[$this->rear]=$value;}//弹出数据publicfunctionpop(){if($this->isEmpty()){thrownew\Exception('队列为空');}$this->front++;}//判断队列是否为空publicfunctionisEmpty(){return$this->front==$this->rear;}//判断队列是否满publicfunctionisFull(){return$this->rear==$this->maxSize-1;}}$arr=newArrayQueue(10);$arr->push(2);$arr->push(2);$arr->push(2);$arr->push(2);$arr->pop();$arr->showQueue();上述队列是有缺陷的。当队列满了，数据就会弹出，不能再插入数据，所以做了一个循环队列来完善功能。数组模拟循环队列思想：1.rear指向队列尾部的最??后一个位置，并约定留一个空格；2.front指向队头；3.当rear=front时，队列为空；4.当front==(rear+1)%maxSize时，队列已满；5、队列长度为：(rear+maxSize-front)%maxSize;classCircleArray{protected$maxSize;受保护的$前面；受保护的$rear；//rear指向最后一个元素，最后一个元素//front指向第一个元素//如果rear=front，则队列为空//if(rear+1)%maxSize=front，则队列已满//队列长度(rear+maxSize-front)%maxSizepublicfunction__construct($maxSize){$this->maxSize=$最大尺寸；$this->front=0;$this->rear=0;$this->arr=[];}//显示队列数据publicfunctionshowQueue(){if($this->isEmpty()){thrownew\Exception('队列为空');}for($i=$this->front;$i<=$this->length();$i++){echo$this->arr[$i%$this->maxSize].'';}}//插入数据publicfunctionpush($value){if($this->isFull()){thrownew\Exception('队列已满');}$this->arr[$this->rear]=$value;$this->rear=($this->rear+1)%$this->maxSize;}//弹出数据publicfunctionpop(){if($this->isEmpty()){thrownew\Exception('队列为空');}$this->front=($this->front+1)%$this->maxSize;}//判断队列是否为EmptypublicfunctionisEmpty(){return$this->front==$this->rear;}//判断队列是否满publiccfunctionisFull(){return($this->rear+1)%$this->maxSize==$this->front;}}//计算队列的长度publicfunctionlength(){return($this->rear+$this->maxSize-$this->front)%$this->maxSize;}}$arr=newCircleArray(5);$arr->push(2);$arr->push(2);$arr->push(2);$arr->push(2);$arr->pop();$arr->push(2);$arr->showQueue();
