数组实现队列

import java.util.Scanner;

/**
 * @author Rainful
 * @create 2021/05/28
 */
class Main2{
    public static void main(String[] args){
        // 创建输入实例
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入队列的大小");
        int arrMaxLength;
        try {
            arrMaxLength = sc.nextInt();
        } catch (Exception e) {
            System.out.println("输入有误, 默认长度为3");
            arrMaxLength = 3;
        }

        ArrQueueDemo2 queue = new ArrQueueDemo2(arrMaxLength);

        boolean flag = true;
        while (flag){
            System.out.println("a 增加一个数据");
            System.out.println("g 弹出一个数据");
            System.out.println("h 打印头部数据");
            System.out.println("p 打印全部数据");
            System.out.println("e 退出程序");

            char c = sc.next().charAt(0);
            switch (c) {
                case ‘a‘ -> {
                        if (queue.isFull()){
                            System.out.println("队列已满");
                            continue;
                        }
                        System.out.println("请输入数据");
                        queue.addQueue(sc.nextInt());
                }
                case ‘g‘ -> {
                    try{
                        queue.getQueue();
                    } catch (Exception e){
                        System.out.println(e.getMessage());
                    }
                }
                case ‘h‘ -> {
                    try{
                        queue.printHeadQueue();
                    } catch (Exception e){
                        System.out.println(e.getMessage());
                    }
                }
                case ‘p‘ -> {
                    try{
                        queue.printQueue();
                    } catch (Exception e){
                        System.out.println(e.getMessage());
                    }
                }
                case ‘e‘ -> {
                    System.out.println("程序关闭");
                    sc.close();
                    flag = false;
                }
            }
        }

    }
}

class ArrQueueDemo2{
    private int arrMaxlength;
    private int tailCount = -1;
    private int[] queue;

    // 接收输入 创建队列
    public ArrQueueDemo2(int arrMaxLength) {
        this.arrMaxlength = arrMaxLength;
        queue = new int[this.arrMaxlength];
    }

    // 判断队列是否为空
    public boolean isEmpty(){
        return this.tailCount == -1;
    }

    // 判断队列是否已满
    public boolean isFull(){
        return this.tailCount == this.arrMaxlength - 1;
    }

    // add 增加一个数据
    public void addQueue(int num){
        this.tailCount++;
        queue[this.tailCount] = num;
    }

    // get 弹出头部数据
    public void getQueue(){
        if (isEmpty()){
            throw new RuntimeException("队列为空");
        }
        System.out.println(queue[0]);
        this.tailCount--;
        for(int i = 0; i < this.arrMaxlength - 1; i++){
            queue[i] = queue[i + 1];
        }
        queue[queue.length -1] = 0;
    }

    // head 打印头部数据
    public void printHeadQueue(){
        if (isEmpty()){
            throw new RuntimeException("队列为空");
        }
        System.out.println("头部数据为: " + queue[0]);
    }

    // print 打印队列全部数据
    public void printQueue(){
        if (isEmpty()){
            throw new RuntimeException("队列为空");
        }
        for (int n : queue){
            System.out.printf("%d\t", n);
        }
        System.out.println();
    }

}

数组实现队列

原文：https://www.cnblogs.com/rainful/p/14824125.html