数组实现队列(循环队列)
package com.dai.queue; import java.util.Scanner; public class CircleArrayQueue { public static void main(String[] args) { //创建一个环形队列对象 CircleArray arrayQueue = new CircleArray(4);//有效空间只有3 char key = ' '; Scanner scanner = new Scanner(System.in); boolean loop = true; while(loop) { System.out.println("s(show):显示队列"); System.out.println("e(exit):退出队列"); System.out.println("a(append):添加数据到队列"); System.out.println("g(get):从队列取出数据"); System.out.println("h(head):查看队列头数据"); key = scanner.next().charAt(0); switch (key) { case 's': arrayQueue.showQueue(); break; case 'a': System.out.println("输入数字:"); int value = scanner.nextInt(); arrayQueue.addQueue(value); break; case 'g': try { int res = arrayQueue.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 = arrayQueue.headQueue(); System.out.printf("队列头的数据是%d\n",res); }catch(Exception e) { System.out.println(e.getMessage()); } break; case 'e': scanner.close(); loop = false; break; default: break; } } System.out.println("程序退出"); } } //使用数组模拟队列,编写一个ArrayQueue类 class CircleArray{ private int maxSize; private int front; private int rear; private int[] arr; public CircleArray(int arrMaxSize) { maxSize = arrMaxSize; arr = new int[maxSize]; } public boolean isFull() { return (rear+1)%maxSize == front; } public boolean isEmpty() { return rear==front; } public void addQueue(int n) { if (isFull()) { System.out.println("队列满,不能加入数据"); return; } arr[rear] = n; rear = (rear+1)%maxSize; } public int getQueue() { if(isEmpty()) { throw new RuntimeException("队列空,不能取数据"); } int value = arr[front]; front = (front+1)%maxSize; return value; } public int size() { return (rear+maxSize-front)%maxSize; } public void showQueue() { if(isEmpty()) { System.out.println("队列空,无数据"); return; } for(int i =front; i<front+size(); i++) { System.out.printf("arr[%d]=%d\n", i%maxSize, arr[i%maxSize]); } } public int headQueue() { if(isEmpty()) { throw new RuntimeException("队列空,无数据"); } return arr[front]; } }