数组模拟循环队列

我会带着你远行 2022-09-06 15:26 253阅读 0赞

package com.example.datastructrue;
    
    import java.util.Scanner;
    
    public class ArrCircleQueue {
        
        public static void main(String[] args) {
        
    
            CircleQueue queue = new CircleQueue(3);
            char key = ' ';
            Scanner scanner = new Scanner(System.in);
            boolean loop = true;
    
            while (loop){
        
                System.out.println("s:显示所有队列");
                System.out.println("e:退出程序");
                System.out.println("a:添加数据");
                System.out.println("g:从队列中取出数据");
                System.out.println("h:查看队列头数据");
                key = scanner.next().charAt(0);
    
                switch (key){
        
                    case 's':queue.showQueue();break;
                    case 'e':loop = false; break;
                    case 'a':
                        System.out.println("输入一个数");
                        int value = scanner.nextInt();
                        queue.addQueue(value);
                        break;
                    case 'g':
                        try {
        
                            int value2 = queue.getQueue();
                            System.out.printf("队列头元素为%d\n",value2);
                        }catch (Exception e){
        
                            System.out.println(e.getMessage());
                        }break;
                    case 'h':
                        try {
        
                            int value3 = queue.headQueue();
                            System.out.printf("队列头元素为%d\n",value3);
                        }catch (Exception e){
        
                            System.out.println(e.getMessage());
                        }
                }
            }
    
        }
    
        static class  CircleQueue{
        
    //        定义一个数组
            private int[] queue;
    //        front为第一个元素的下标值，默认为0
            private int front = 0;
    //        rear为最后一个元素的下标值加1，默认为0
            private int rear = 0;
    //        数组的最大容量
            private int maxSize;
    
    //        通过构造函数创建一个数组
         public    CircleQueue(int maxSize){
        
                this.maxSize = maxSize;
                this.queue = new int[this.maxSize];
            }
    
    //        判断环形队列是否满了
            public boolean isFull(){
        
             return (this.rear+1)%this.maxSize==front;
            }
    
    //        判断环形队列是否为空
            public boolean isEmpty(){
        
             return this.front == this.rear;
            }
    
    //        添加数据
            public void addQueue(int x) {
        
                if (isFull()) {
        
                    System.out.println("队列已满，添加失败");
                    return;
                } else {
        
                    this.queue[rear] = x;
    //             因为是环形队列，所以得使用取模的形式进行循环使用队列
                    this.rear = (this.rear + 1) % this.maxSize;
                }
            }
    
    
    //        获取数据
                public int getQueue(){
        
                    if (isEmpty()){
        
                        throw new RuntimeException("循环队列为空,获取数据失败");
                    }
                    int val = this.queue[this.front];
                    this.front = (this.front+1)%this.maxSize;
                    return val;
                }
    
    
    //            显示循环队列的所有数据
            public void showQueue(){
        
             for (int i =this.front;i<this.front+this.size();i++){
        
                 System.out.printf("arr[%d]=%d\n",i%this.maxSize,this.queue[i%this.maxSize]);
             }
            }
    
    //        求出队列中的数据个数
            public int size(){
        
             return (this.rear+this.maxSize-this.front)%this.maxSize;
            }
    
    //        显示头元素
            public int headQueue(){
        
             if(isEmpty()){
        
                 throw new RuntimeException("循环队列为空,获取数据失败");
             }
             return this.queue[this.front];
            }
        }
    }