单链表----递归建立，递归反转，递归打印

/*
*    auther: Try86
*    time:2012/9/25 13:14
*    dec:单链表：递归建立，递归反转，递归打印
*/

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

typedef struct list                 //单链表节点结构
{
   int data;
   struct list *p_next;
}List;

int main(void)
{
   int num = 0;                    //统计单链表的节点数
   List *head = NULL;              //链表头指针
   List *p_cur = NULL;
   void build_list(List **head, List *p_cur, int *pnum);   
   void list_reverse(List **head, List *p_cur, List *p_nt, int *pnum);
   void print(List *ptr);

   build_list(&head, p_cur, &num);
   assert(NULL != head);           //判断是否为空表

   list_reverse(&head, head, head->p_next, &num);
   print(head);

   return 0;
}

//递归建立单链表
void build_list(List **head, List *p_cur, int *pnum)
{
   int num;
   List *ptr = NULL;

   if (scanf("%d", &num) && num > 0)
   {
      ++(*pnum);
      if ((ptr = (List *)malloc(sizeof(List))) != NULL)
      {
         ptr->data = num;
         ptr->p_next = NULL;
         if (NULL == *head)
         {
            *head = ptr;
            p_cur = ptr;
            p_cur->p_next = ptr->p_next;
         }
         else
         {
            p_cur->p_next = ptr;
            p_cur = p_cur->p_next;
         }
         build_list(head, p_cur, pnum);
      }
   }

}

//递归反转单链表
void list_reverse(List **head, List *p_cur, List *p_nt, int *pnum)
{
   if (NULL == p_nt)
   {
      *head = p_cur;
      --(*pnum);
      return ;
   }

   list_reverse(head, p_cur->p_next, p_nt->p_next, pnum);
   p_nt->p_next = p_cur;
   --(*pnum);
   if (0 == *pnum)
   {
      p_cur->p_next = NULL;
   }

}

//递归打印单链表
void print(List *ptr)
{
   if (NULL != ptr)
   {
      printf("%d\t", ptr->data);
   }
   else
   {
      return ;
   }

   print(ptr->p_next);
}