技術標籤：資料結構

佇列的特性是：先進先出；

package com.vicbaily.queue;

public class ArrayQueueDemo {

    public static void main(String[] args) {
        int maxSize = 3 ;
        ArrayQueue queue = new ArrayQueue(maxSize);
        for (int index = 0; index < maxSize; index++) {
            double value = Math.random();
            System.out.print(value + "\t");
            queue.addQueue(value);
        }
        System.out.println();
        System.out.println("==================================");
        for (int index = 0; index < maxSize; index++) {
            System.out.print(queue.getQueue() + "\t");
        }
    }

}

class ArrayQueue {
    private int maxSize; // 最大容量
    private int front; // 字首指標
    private int rear; // 字尾指標
    private double[] arr; // 佇列容量

    // 佇列構造器，建立容量
    public ArrayQueue(int maxSize) {
        this.maxSize = maxSize;
        arr = new double[maxSize];
        front = -1;
        rear = -1;
    }

    public boolean isFull(){
        return maxSize == rear + 1;
    }

    public boolean isEmpty() {
        return rear == front;
    }

    public void addQueue(double n) {
        if (isFull()) {
            System.out.println("佇列已經滿了");
            return;
        }
        rear++;
        arr[rear] = n;
    }


    public double getQueue() {
        if (isEmpty()) {
            throw new RuntimeException("佇列為空");
        }
        front++;
        return arr[front];
    }

    public void showQueue() {
        if (isEmpty()) {
            System.out.println("佇列為空");
            return;
        }

        for (int index = 0; index < arr.length; index++) {
            System.out.printf("%d\t", arr[index]);
        }
    }

    public double headQueue() {
        if (isEmpty()) {
            throw new RuntimeException("佇列為空");
        }
        return arr[front + 1];
    }

}
 

執行結果為：

0.5237874587129546	0.5958271076564382	0.9547179942382022	
==================================
0.5237874587129546	0.5958271076564382	0.9547179942382022