chain stack

/* chain stack
       A stack implemented with a singly linked list

*
*
*/

package com.tulun;

public class TestMl2 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
         LinkStack link=new LinkStack();
         for(int i=0;i<10;i++){
            link.insertHead(i);
         }
         link.show();
         link.pop();
         link.show();
         int a=link.getTop();
         System.out.println(a);
    }

}
class LinkStack{
    class Entry{
        int data;
        Entry next;
        public Entry(){
            this.data = -1;
            this.next = null;
        }
        public Entry(int data){
            this.data=data;
            this.next=null;
        }
    }
    private Entry head=null;
    public LinkStack(){
        this.head=new Entry();
    }
    // Push into the stack and use the head insertion method to make it easier 
    public  void insertHead( int val){
        Entry entry=new Entry(val);
        entry.next=head.next;
        head.next=entry;
    }
    // Only the first data node after the first node to pop out of the stack 
    public  void pop(){
        Entry cur=head.next;
        if(cur==null){
            return;
        }
        head.next=cur.next;
        cur=null;
        return;
    }
    // Get the top element of the stack 
    public  int getTop(){
         return  this .head.next.data;
    }
    public void show(){
        Entry cur=this.head.next;
        while(cur!=null){
            System.out.println(cur.data);
            cur=cur.next;
        }
        System.out.println();
    }
}