环形数组实现队列

数组实现队列

public class ArrayImplementsQueue {
    private int[] arr;
    private int pushIndex;
    private int pollIndex;
    private int size;
    private int limit;

    public ArrayImplementsQueue(int num) {
        this.arr = new int[num];
        this.pushIndex = 0;
        this.pollIndex = 0;
        this.size = 0;
        this.limit = num;
    }

    public void push(int value) {
        if (size == limit) {
            throw new RuntimeException("数组已满，无法添加");
        }
        size++;
        arr[pushIndex]=value;
        pushIndex = newIndex(pushIndex);
    }
    
    public int poll() {
        if (size == 0) {
            throw new RuntimeException("数组已空，无法弹出");
        }
        size--;
        int a=arr[pollIndex];
        pollIndex = newIndex(pollIndex);
        return a;
    }
    
    public int newIndex(int i) {
        return i < limit - 1 ? i + 1 : 0;
    }
}