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);

}