需要注意的是
队列容量为maxSize - 1
判断队列为空 rear == front
判断是否为满 (rear + 1) % maxSize == front
或者 (rear - front + maxSize) % maxSize == maxSize - 1
获取元素个数：(rear + maxSize - front) % maxSize
class AnnularArrayQueue {private int maxSize;private int front;//队列头private int rear;//队列尾private int[] arr;//模拟队列//初始化public AnnularArrayQueue(int arrMaxSize) {maxSize = arrMaxSize;front = 0;//指向队列头部前一个位置rear = 0;//指向队列尾部（即包含最后一个数据）arr = new int[arrMaxSize];}//判断队列满public boolean isFull() {System.out.println((rear + 1) % maxSize == front);//return (rear + 1) % maxSize == front;return (rear - front + maxSize) % maxSize == maxSize - 1;}//判断队列是否为空public boolean isEmpty() {return rear == front;}//队列添加数据public void addQueue(int n) {if (isFull())return;arr[rear] = n;rear = (rear + 1) % maxSize;}//出队列public int pullQueue() {if (isEmpty())throw new RuntimeException("Queue Empty!");int data = arr[front];front = (front + 1) % maxSize;return data;}//显示队列数据public void showQueue() {if (isEmpty())System.out.println("空");for (int i = front; i < front + getSize(); i++) {System.out.print("array[" + i + "]=" + arr[i%maxSize] + "\n");}}//显示头数据public int headQueue() {if (isEmpty())throw new RuntimeException("Queue Empty!");return arr[front];}//获取元素个数public int getSize(){return (rear - front +maxSize) % maxSize;}}
