using System;

namespace DstrQueue
{
    /// <summary>
    /// Class1 的摘要说明。
    /// </summary>
    class QueueNode
    {
        Object item;
        QueueNode link;
    }
    class Queue
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main(string[] args)
        {
            //
            // TODO: 在此处添加代码以启动应用程序
            //
        }
        private QueueNode front;
        private QueueNode rear;
        private int count;

        public boolean empty()
        {
            return (count==0);
        }

        public void insert(Object newItem)
        {
            QueueNode temp=new QueueNode();
            temp.item=newItem;
            temp.link=null;
            if(rear==null)
            {
                front=rear=temp;
            }
            else
            {
                rear.link=temp;
                rear=temp;
            }
            count++;
        }
        public Object remove()
        {
            if(count==0)
                return null;
            else
            {
                Object tempItem=front.item;
                front=front.link;
                if(front==null)
                {
                    rear=null;
                }
                count--;
                return tempItem;
            }
        }
    }
}