using System;

namespace DataStructure

{

 /// <summary>

 /// Class1 的摘要说明。

 /// </summary>

 public class Stack//栈类

 {

  private int count=0;

        private Node first=null;//定义首结点

  public bool Empty

  {

   get

   {

    return(first==null);

   }

  }

  public int Count

  {

   get

   {

    return count;

   }

  }

  public object Pop()//入栈

  {

   if(first==null)

   {

    throw new InvalidOperationException("Can not pop from an empty stack;");

   }

   else

   {

    object temp=first.Value;

    first=first.Next;

    count--;

    return temp;

   }

  }

  public void push(object o)//出栈

  {

   first=new Node(o,first);

   count++;

  }

  public Stack()

  {

   //

   // TODO: 在此处添加构造函数逻辑

   //

  }

 }

 class Node //结点类

 {

  public Node Next;

  public object Value;

  public Node(object value):this(value,null){}

  public Node(object value,Node next)

  {

         Next=next;

  Value=value;

  }

 }

}