数据结构与算法——队列

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import javax.management.RuntimeErrorException;

/**
 *  *队列的数组实现
 * @author 蜡笔小新
 *
 */
public class Test3 {

	public static void main(String []args) {
		 boolean temp=true;
		 ArrQueue arrQueue=new ArrQueue(3);
		 while(temp) {
			 System.out.println("isFull:队列是否为满");
			 System.out.println("isEmpty:队列是否为空");
			 System.out.println("add:添加元素");
			 System.out.println("getOne:获取元素");
			 System.out.println("getHead:获取头部元素");
			 System.out.println("getQueue:获取队列");
			 System.out.println("size:获取队列中元素的个数");
			 System.out.println("exit:退出程序");
			 System.out.println("输入你的操作命令：");
			 Scanner scanner=new Scanner(System.in);
			 String str=scanner.nextLine();
			switch(str) {
			    case "isFull":
			    	System.out.println(arrQueue.isFull());
			    	break;
			    case "isEmpty":
			    	System.out.println(arrQueue.isEmpty());
			    	break;
			    case "add":
			    	System.out.println("输入要添加的数据：");
			    	int n=scanner.nextInt();
			    	arrQueue.add(n);
			    	break;
			    case "getOne":
					try {
						int m = arrQueue.getOne();
						System.out.println(m);
					} catch (Exception e) {
						System.out.println(e.getMessage());
					}
			    	break;
			    case "getHead":
			    	try {
						int s=arrQueue.getHead();
						System.out.println(s);
					} catch (Exception e) {
						// TODO: handle exception
						System.out.println(e.getMessage());
					}
			    	break;
			    case "getQueue":
			    	try {
						System.out.println(arrQueue.getQueue());
					} catch (Exception e) {
						// TODO: handle exception
						System.out.println(e.getMessage());
					}
			    	break;
			    case "size":
			    	System.out.println(arrQueue.size());
			    	break;
			    case "exit":
			    	temp=false;
			    	break;
			    default:
			    	System.out.println("输入有误");
			    	break;
			 }
		 }
		 System.out.println("程序退出！");
	}
	
}

class ArrQueue{
	private int maxSize; //队列的最大容量
	private int front; //队列头
	private int rear; //队列尾
	private int []arr; //模拟队列
	
	public ArrQueue(int maxSize) {
		this.maxSize=maxSize;
		front=-1; //指向头部的前一个位置
		rear=-1; //指向尾部的位置
		arr=new int[maxSize]; //初始化数组
	}
	
	//判断队列是否为空
	public boolean isEmpty() {
		return front==rear;
	}
	//判断队列是否为满
	public boolean isFull() {
		return rear==maxSize-1;
	}
	
	//向队列中添加元素
	public void add(int data) {
		if(isFull()) {
			System.out.println("队列已满");
			return ;
		}
		arr[++rear]=data;
	}
	//从队列中去除元素
	public int getOne() throws Exception{
		if(isEmpty()) {
			throw new Exception("队列为空");
		}
		
	  return arr[++front];
		
	}
	//size()	int	无	获取队列中元素的个数
	//getHead()	int	无	获取头部元素
	public int getHead() throws Exception {
		if(isEmpty()) {
			throw new Exception("队列为空");
		}
	  return arr[front+1];
	}
	
	//获取队列元素
	public List getQueue() {
		if(isEmpty()) {
			throw new RuntimeException("队列为空");
		}
		List list=new ArrayList<>();
		for(int i=front+1;i<=rear;i++) {
			list.add(arr[i]);
		}
		return list;
	}
	
	//获取队列元素个数
	public int size() {
		if(isEmpty()) {
			return 0;
		}
		return rear+1;
	}
}

//从队列中去除元素
	public int getOne() throws Exception{
		if(isEmpty()) {
			throw new Exception("队列为空");
		}
		
	  int t=arr[++front];
	  if(isEmpty()) {
		  front=rear=-1;
	  }
	  else {
		  for(int i=front+1;i<=rear;i++) {
			  arr[i-1]=arr[i];
		  }
		  front--;
		  rear--;
	  }
	  return t;
		
	}