用数组实现队列

秒速五厘米 2021-11-23 03:06 312阅读 0赞

第一个只能用一次先是创造数据结构（最大值，俩索引，存数据的），用构造器初始化，判断空或者满，增加，取出

package com.sparseArray.queue;
    
    //使用数据模拟队列
    class ArrayQueue{
        private int maxSize;
        private int front;
        private int rear;
        private int arr[];
    
        //创建构造器(用来初始化)
        public ArrayQueue(int arrmaxSize){
            maxSize = arrmaxSize;
            arr = new int[maxSize];
            front = -1;//指向队列头的前一个位置
            rear = -1;//指向队尾
        }
    
        public boolean isFull(){
            return  rear == maxSize - 1;
        }
        public  boolean isEmpty(){
            return rear  == front;
        }
    
        public void addQueue(int n){
            if (isFull()){
                System.out.println("队列已满");
                return;
            }
            rear++;//rear后移
            arr[rear] = n;
        }
        //获取队列数据，出队列
        public int getQueue(){
            if(isEmpty()){
                throw new RuntimeException("队列空，无数据");
            }
            front++;//front后移
            return arr[front];
        }
        //显示队列所有数据
        public void showQueue(){
            if(isEmpty()){
                System.out.println("队列空，无数据");
                return;
            }
            for (int i = 0; i <arr.length ; i++) {
                System.out.printf("arr[%d]=%d\n",i,arr[i]);
            }
        }
    
        //显示队列的头数据
        public int headQueue(){
            if(isEmpty()){
                throw new RuntimeException("队列空，无数据");
            }
            return arr[front+1];
        }
    }

测试

package com.sparseArray.queue;
    
    import java.util.Scanner;
    
    /**
     * @Auther: 大哥的叔
     * @Date: 2019/7/25 08:44
     * @Description:
     */
    public class ArrayQueueDemo {
        public static void main (String[] args) {
        //测试
            ArrayQueue queue = new ArrayQueue(3);
            char key = ' ';//接收用户输入
            Scanner scanner = new Scanner(System.in);
            boolean loop = true;
            while (loop){
                System.out.println("s(show):显示队列");
                System.out.println("e:退出");
                System.out.println("a:添加");
                System.out.println("g:取出");
                System.out.println("h:查看队列头的数据");
                key = scanner.next().charAt(0);//接收一个字符
                switch (key){
                    case 's':
                        queue.showQueue();break;
                    case 'a':
                        System.out.println("输出一个数");
                        int value = scanner.nextInt();
                        queue.addQueue(value);break;
                    case 'g':
                        try {
                            int res = queue.getQueue();
                            System.out.printf("取出的数据是%d\n",res);
                        } catch (Exception e) {
                            System.out.println(e.getMessage());
                        }break;
    
                    case 'h':
                        try {
                            int res = queue.headQueue();
                            System.out.printf("头数据是%d\n",res);
                        } catch (Exception e) {
                            System.out.println(e.getMessage());
                        }break;
                    case 'e':
                        scanner.close();
                        loop = false;
                        break;
                        default:
                            break;
                }
    
            }
            System.out.println("退出");
        }
    }