package com.dbstructor.oop2;


class Link {
    public int iData;
    public double dData;
    public Link next; 
    
    public Link(int id, double dd){
        iData = id;
        dData = id;
    }
    
    public void displayLink(){
        System.out.print("{" + iData + "," + dData + "}");
    }
}
class LinkList {
    private Link first;
    public LinkList(){
        first = null;
    }
    
    public boolean isEmpty(){
        return (first == null);
    }
    
    // 插入链接点
    public void insertFirst(int id, double dd){
        Link newLink = new Link(id, dd);
        newLink.next = first;
        first = newLink;
    }
    
    // 删除链接点
    public Link deleteFirst(){
        Link temp = first;
        first = first.next;
        return temp;        
    }
    
    public void displayList(){
        System.out.print("List (first-->last): ");
        Link current = first;
        while(current != null){
            current.displayLink();
            current = current.next;
        }
        System.out.println("");
    }
}

public class LinkListApp {

    public static void main(String[] args) {
        LinkList theList = new LinkList();
        theList.insertFirst(22, 2.99);
        theList.insertFirst(44, 4.99);
        theList.insertFirst(66, 6.99);
        theList.insertFirst(88, 8.99);
        
        theList.displayList();
        
        while(!theList.isEmpty()){
            Link aLink = theList.deleteFirst();
            System.out.print("Deleted ");
            aLink.displayLink();
            System.out.println("");
        }
        
        theList.displayList();

    }

}