#include <iostream>

 using namespace std;

 class Node

 {

 public:

     Node(int v, Node* n)

     {val = v;

     next = n;}

     ~Node(){}

     int val;

     Node* next;

 };

 Node * phead = NULL;

 void AddNode(int val)

 {

     Node* pnode = new Node(val,NULL);

     //Node one_node(val,NULL); 这里有大bug！如果这样写，在函数退出时自动调用析构函数！链表就乱了！

     if(phead == NULL)

     {

         phead = pnode;

     }

     else

     {

         Node* p = phead;

         while(p->next != NULL)

         {

             p = p->next;

         }

         p->next = pnode;

     }

 }

 void PrintLink()

 {

     Node* p = phead;

     while(p != NULL)

     {

         int temp = p->val;

         cout<<temp<<endl;

         p = p->next;

     }

 }

 Node* FindNthFromTail(int n) //n >= 1, linklist counts from 1 to n

 {

     Node* pfast;

     Node* pslow;

     if(phead == NULL)

     {

         cout<<"Empty Link!"<<endl;

         return NULL;

     }

     else if(n<=)

     {

         cout<<"Illegal N!"<<endl;

         return NULL;

     }

     else

     {

         pfast = phead;

         pslow = phead;

         for(int i=; i<n; i++)

         {

             if(pfast->next != NULL)

                 pfast = pfast->next;

             else

                 {

                     cout<<"Illegal N!"<<endl;

                     return NULL;

                 }

         }

         while(pfast->next != NULL)

         {

             pslow = pslow->next;

             pfast = pfast->next;

         }

         return pslow;

     }

 }

 int main()

 {

     int val,n,flag;

     Node* pfind;

     cin>>val;

     while(val != )

     {

         AddNode(val);

         cin>>val;

     }

     PrintLink();

     cout<<"Input the node number you want to find form tail:"<<endl;

     cin>>n;

     pfind = FindNthFromTail(n);

     if(pfind)

     {

         cout<<"Find!"<<endl<<"The key value is:"<<pfind->val<<endl;

     }

     return ;

 }