队列结构：先进先出，First In First Out
import java.util.LinkedList;
class Queue{
private LinkedList<Object> link;
Queue(){
link = new LinkedList<Object>();
}
public void Add(Object obj){
  link.addFirst(obj);
}
public Object get(){
  return link.removeLast();
}
public boolean isNull(){
  return link.isEmpty();
}
}
public class QueueDemo {
   public static void main(String[] args){
    Queue q = new Queue();
    q.Add("hello");
    q.Add("world");
    while(! q.isNull())
     System.out.println(q.get());
   }
}

一点注释都不写的啊？

我当时写的时候忘了把存入封装成方法了