package com.test;

public class MyCircularQueue {
int[] data;
int tail;
int head;
int size;

/** Initialize your data structure here. Set the size of the queue to be k. */
public MyCircularQueue(int k) {
    data = new int[k];
    tail = -1;
    head = -1;
    size = 0;

}

/** Insert an element into the circular queue. Return true if the operation is successful. */
public boolean enQueue(int value) {
    if(isFull()){
        return false;
    }
    if(isEmpty()){
        head = 0;
    }
    tail = (tail+1)%data.length;
    data[tail] = value;
    size += 1;
    return true;

}

/** Delete an element from the circular queue. Return true if the operation is successful. */
public boolean deQueue() {
    if(isEmpty()){
        return false;
    }
    if (head == tail) {
        head = -1;
        tail = -1;
        return true;
    }
    head = (head+1)%data.length;
    size -= 1;
    return true;
}

/** Get the front item from the queue. */
public int Front() {
    if(isEmpty()){
        return -1;
    }
    return data[head];

}

/** Get the last item from the queue. */
public int Rear() {//报错位置在这里，报的事数组越界。
    if(isEmpty()){
        return -1;
    }
    return data[tail];
}

/** Checks whether the circular queue is empty or not. */
public boolean isEmpty() {
   // return size == 0?true:false; //用这一句做返回的时候会报数组越界
    return head == -1; //这一句却不会报错
}

/** Checks whether the circular queue is full or not. */
public boolean isFull() {
   // return size == data.length?true:false; //用这一句做返回的时候会报数组越界

    return ((tail + 1) % data.length) == head;//这一句却不会报错
}

}

测试代码如下：

package com.test;

public class test {
public static void main(String[] args) {
MyCircularQueue myCircularQueue = new MyCircularQueue(1);
System.out.println( myCircularQueue.enQueue(1));
System.out.println( myCircularQueue.enQueue(2));
System.out.println( myCircularQueue.enQueue(3));
System.out.println( myCircularQueue.enQueue(4));
System.out.println( myCircularQueue.Rear());
System.out.println( myCircularQueue.isFull());
System.out.println( myCircularQueue.deQueue());
System.out.println( myCircularQueue.enQueue(4));
System.out.println( myCircularQueue.Rear());//这里报错了，报数组越界
}
}

求大神帮忙看看，谢谢