数据结构之队列

  1 package Queue;
  2 
  3 import java.util.Scanner;
  4 
  5 public class ArrayQueue {
  6 
  7     public static void main(String[] args) {
  8         ArrayQueue arrayQueue = new ArrayQueue(6);
  9         Scanner scanner = new Scanner(System.in);
 10         char key = ‘ ‘;
 11         boolean loop = true;
 12         while (loop) {
 13             System.out.println("a 入队");
 14             System.out.println("r 出队");
 15             System.out.println("g 遍历队列");
 16             System.out.println("h 查看队头元素");
 17             key = scanner.next().charAt(0);//接收一个字符串
 18             switch (key) {
 19                 case ‘a‘:
 20                     System.out.println("输入一个数");
 21                     int value = scanner.nextInt();
 22                     arrayQueue.addQueue(value);
 23                     break;
 24                 case ‘r‘:
 25                     try {
 26                         int removeNum = arrayQueue.removeQueue();
 27                         System.out.println("取出的数据为：" + removeNum);
 28                     } catch (Exception e) {
 29                         System.out.println(e.getMessage());
 30                     }
 31                     break;
 32                 case ‘g‘:
 33                     try {
 34                         arrayQueue.getAllQueue();
 35                     } catch (Exception e) {
 36                         System.out.println(e.getMessage());
 37                     }
 38                     break;
 39                 case ‘h‘:
 40                     try {
 41                         int headNum = arrayQueue.headQueue();
 42                         System.out.println("队头为："+headNum);
 43                     }catch (Exception e){
 44                         System.out.println(e.getMessage());
 45                     }
 46             }
 47         }
 48     }
 49 
 50     int maxSize;
 51     int rear;
 52     int front;
 53     int arr[];
 54 
 55     public ArrayQueue(int arrMaxSize){
 56         maxSize = arrMaxSize;
 57         rear = -1;
 58         front = -1;
 59         arr = new int[maxSize];
 60     }
 61 
 62     //判断队列是否为空
 63     public boolean isEmpty(){
 64         return rear == front;
 65     }
 66 
 67     //判断队列是否已满
 68     public boolean isFull(){
 69         return rear == maxSize-1;
 70     }
 71 
 72     //入队
 73     public void addQueue(int num){
 74         if (isFull()){
 75             System.out.println("队列满的");
 76             return;
 77         }
 78         rear++;
 79         arr[rear] = num;//入队
 80     }
 81 
 82     //出队(单个元素）
 83     public int removeQueue(){
 84         if (isEmpty()){
 85             throw new RuntimeException("队列没有元素");
 86         }
 87         front++;
 88         return arr[front];
 89     }
 90 
 91     //遍历队列所有元素
 92     public void getAllQueue(){
 93         if (isEmpty()){
 94             throw new RuntimeException("队列为空");
 95         }
 96         for (int i = 0 ; i <= arr.length ; i++){
 97             System.out.println("队列元素下标："+i+"   "+"队列元素值:"+arr[i]);
 98         }
 99     }
100 
101     //查看队头元素
102     public int headQueue(){
103         if (isEmpty()){
104             throw new RuntimeException("队列为空");
105         }
106         return arr[front+1];
107     }
108 }