ccccccccccccccccccccccccccccccc

#include "stdafx.h"
#include<stdio.h>
#include<stdlib.h>
#include<string.h>

struct node{
   char c;
   struct node *next;
};
typedef struct node *Link;

Link init(Link head){
   //Link head;
   Link before;
   Link newnode;
   Link tail;

   int i, num;
   char str[101];
   //初始字符串的输入
   scanf("%s",str);
   num = strlen(str);

// head = (Link)malloc(sizeof(struct node));
// if(!head)
// return;
   head->c = str[0];
   head->next = NULL;
   before = head;
   //讲初始字符串接入链表
   for(i=1;i<num;i++){
      newnode = (Link)malloc(sizeof(struct node));
      if(!newnode)
         return NULL;
      newnode->c = str[i];
      newnode->next = NULL;
      before->next = newnode;
      before = newnode;
   }
   newnode->next = head;
   tail = newnode;
   return tail;
}

void Insert(Link *L,char ch){
   Link p,s;
   p = *L;
   s = (Link)malloc(sizeof(struct node));

   s->c = ch;
   //
   s->next = p->next;
   p->next = s;
   //指针后移
   p = p->next;
   *L = p;
}

void Delete(Link *L){
   Link p,q;
   p = *L;
   q = p->next;
   p->next = q->next;
   free(q);
   *L = p;
}
void print(Link head, Link tail){
   Link p;
   //p = head;
   tail->next=NULL;
   do
   {
      p = head;
      printf("%c",head->c);
      head = head->next;
      free(p);
   }while(head!=NULL);
}

int _tmain(int argc, _TCHAR* argv[])
{
   char ch;
   int i;
   int playnum;
   int choose;
   Link head;
   Link tail;
   head = (Link)malloc(sizeof(struct node));
   freopen("linklist_i.txt","r",stdin);
   freopen("linklist_o.txt","w",stdout);
   setbuf(stdout,NULL);
   scanf("%d", &playnum);
   tail=init(head);

   for(i=0;i<playnum;i++){
      scanf("%d", &choose);

      if(choose==1){
         scanf(" %c",&ch);
         Insert(&tail,ch);
      }else if(choose==2){
         if(!(tail->next==tail)){
            Delete(&tail);
         }

      }else if(choose==3){
         tail = tail->next;
      }
   }

   print(head,tail);
   printf("\n");
   return 0;
}

出师一表真名世,千载谁堪伯仲间.