using System;
using System.IO;
// 構(gòu)成鏈表的結(jié)點定義 
public class Node 
{
 public Object data;
 public Node next;
 public Node( Object d ) 
 {
 data = d;
 next = null;
 }
}
public class List 
{
 // 用變量來實現(xiàn)表頭
 private Node Head = null;
 private Node Tail = null;
 private Node Pointer = null;
 private int Length = 0;
 //清空整個鏈表 
 public void deleteAll( ) 
 {
 Head = null;
 Tail = null;
 Pointer = null;
 Length = 0;
 }
 //鏈表復(fù)位，使第一個結(jié)點 成為當(dāng)前結(jié)點
 public void reset( ) 
 {
 Pointer = null;
 }
 //判斷鏈表是否為空
 public bool isEmpty( ) 
 {
 return (Length == 0);
 }
 //判斷當(dāng)前結(jié)點是否 為最后一個結(jié)點
 public bool isEnd( ) 
 {
 if (Length == 0)
  throw new System.Exception( );
 else if (Length == 1)
  return true;
 else
  return (cursor( ) == Tail);
 }
 //返回當(dāng)前結(jié)點的下一個結(jié)點的值， 并使其成為當(dāng)前結(jié)點
 public Object nextNode( ) 
 {
 if (Length == 1)
  throw new System.Exception( );
 else if (Length == 0)
  throw new System.Exception( );
 else 
 {
  Node temp = cursor();
  Pointer = temp;
  if (temp != Tail)
  return (temp.next.data);
  else
  throw new System.Exception( );
 }
 }
 //返回當(dāng)前結(jié)點的值
 public Object currentNode( ) 
 {
 Node temp = cursor( );
 return temp.data;
 }
 //在當(dāng)前結(jié)點前插入一個結(jié)點， 并使其成為當(dāng)前結(jié)點
 public void insert( Object d ) 
 {
 Node e = new Node( d );
 if (Length == 0) 
 {
  Tail = e;
  Head = e;
 } 
 else 
 {
  Node temp = cursor( );
  e.next = temp;
  if (Pointer == null)
  Head = e;
  else
  Pointer.next = e;
 }
 Length++;
 }
 //返回鏈表的大小
 public int size( ) 
 {
 return Length;
 }
 //將當(dāng)前結(jié)點移出鏈表，下一個結(jié)點成為當(dāng)前結(jié)點
 //如果移出的結(jié)點是最后一個結(jié)點，則第一個結(jié)點成為當(dāng)前結(jié)點
 public Object remove( ) 
 {
 Object temp;
 if (Length == 0)
  throw new System.Exception( );
 else if (Length == 1) 
 {
  temp = Head.data;
  deleteAll( );
 } 
 else 
 {
  Node cur = cursor( );
  temp = cur.data;
  if (cur == Head)
  Head = cur.next;
  else if (cur == Tail) 
  {
  Pointer.next = null;
  Tail = Pointer;
  reset( );
  } 
  else
  Pointer.next = cur.next;
  Length--;
 }
 return temp;
 }
 //返回當(dāng)前結(jié)點的指針
 private Node cursor( ) 
 {
 if (Head == null)
  throw new System.Exception( );
 else if (Pointer == null)
  return Head;
 else
  return Pointer.next;
 }
 //鏈表的簡單應(yīng)用舉例
 public static void Main( ) 
 {
 List a = new List();
 for (int i = 1; i <= 10; i++)
  a.insert( new IntPtr(i));
 Console.WriteLine(a.currentNode( ));
 while (!a.isEnd( ))
  Console.WriteLine(a.nextNode( ));
 a.reset();
 while (!a.isEnd( )) 
 {
  a.remove( );
 }
 a.remove( );
 a.reset( );
 if (a.isEmpty( ))
  Console.WriteLine("There is no Node in List!");
 Console.WriteLine("You can press return to quit!");
 try 
 {
  // 確保用戶看清程序運行結(jié)果
  Console.Read( );
 } 
 catch (IOException e) 
 {
 }
 }
}