Java實現數據結構的循環隊列

package com.lee.queue;

public class Queue {
	private int maxSize;//隊列長度
	private int front;	//指向隊列第一個元素的位置，默認值爲0
	private int rear;	//指向隊列最後一個元素的後一個位置，默認值是0
	private int[] data; //存儲隊列的數組
	
	//初始化隊列
	public Queue(int maxSize) {
		this.maxSize = maxSize;
		data = new int[maxSize];
		front = 0;
		rear = 0;
	}
	
	//判斷隊列是否爲空
	public boolean isNull() {
		return front == rear;
	}
	
	//判斷隊列是否爲滿
	public boolean isFull() {
		return (rear + 1) % maxSize == front;
	}
	
	//入隊
	public void addQueue(int element) {
		//判斷隊列是否爲滿
		if(isFull()) {
			System.out.println("隊列滿，不能加入");
			return;
		}
		data[rear] = element;
		//將rear後移,考慮取模
		rear = (rear + 1) % maxSize;
	}
	
	//出隊
	public int getQueue() {
		//判斷是否爲空
		if(isNull()) {
			throw new RuntimeException("隊列爲空，不能取數據");
		}
		int value = data[front];
		//front後移，考慮取模
		front = (front + 1) % maxSize;
		return value;
	}
	
	//顯示隊列所有數據
	public void show() {
		if(isNull()) {
			System.out.println("隊列空，沒有數據");
			return;
		}
		for(int i = front; i < front + size(); i++) {
			System.out.println("data[" + i % maxSize + "]:" + data[i % maxSize]);
		}
	}
	
	//返回有多少個有效元素
	public int size() {
		return (rear + maxSize - front) % maxSize;
	}
	
	//顯示隊列頭數據
	public int peek() {
		if(isNull()) {
			throw new RuntimeException("隊列爲空");
		}
		return data[front];
	}
	
	
}