#include <stdio.h>

 #include <stdlib.h>

 typedef struct linklist

 {

     unsigned int count;

     struct linklist *next;

 }linklist;

 linklist* CreatLinklist(int len)

 {

     linklist *head = NULL, *pre = NULL;

     head = (linklist*)malloc(sizeof(linklist));//头指针。

     pre = (linklist*)malloc(sizeof(linklist)); //pre-previous, 前一个;相对于head来说是后一个。

     printf("Please input the data:\n");

     scanf("%u", &pre->count);

     head->next = pre; //head的后一个是pre。

     pre->next = NULL; //pre的next是NULL。

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

     {

         linklist* tmp = (linklist*)malloc(sizeof(linklist));

         scanf("%u", &tmp->count);

         pre->next = tmp; //新加的节点放在pre后。

         tmp->next = NULL; //新加节点的next是NULL。

         pre = tmp; //新加的节点变成pre，等待下一个tmp。

     }

     return head;

 }

 int Outputlinklist(linklist *head)

 {

     printf("#### Output linklist.\n");

     if (head != NULL)

     {

         while (head->next != NULL)

         {

             printf("%u\n", head->next->count);

             head = head->next;

         }

     }

 }

 int Lenlinklist(linklist *head)

 {

     int len = ;

     if (NULL == head->next)

         return len;

     len++;

     linklist *p = NULL;

     p = head->next;

     while(p->next != NULL)

     {

         len++;

         p = p->next;

     }

     return len;

 }

 int InsertLinklist(linklist *head, int index)

 {

     int len = ;

     len = Lenlinklist(head);

     printf("the length of linklist:%d, the insert index:%d\n", len, index);

     if (index <  || index > len)

         return -;

     int cur_index = ;

     linklist *p = NULL;

     p = head->next;

     while(cur_index < index)

     {

         p = p->next;

         cur_index++;

     }

     linklist *node = (linklist*)malloc(sizeof(linklist));

     printf("Please input the new node data:\n");

     scanf("%u", &node->count);

     node->next = p->next;

     p->next = node;

     return ;

 }

 int DeleteNode(linklist *head, int index)

 {

     int len = ;

     len = Lenlinklist(head);

     if((index < ) || (index > len))

         return -;

     int cur_index = ;

     linklist *p = NULL;

     linklist *q = NULL;

     p = head->next;

     while(cur_index < index)

     {

         p = p->next;

         cur_index++;

     }

     q = p->next;

     p->next = q->next;

     free(q);

     q = NULL;

 }

 linklist *Reverselinklist(linklist *head)

 {

     linklist *p=NULL, *pre=NULL, *pnext=NULL;

     p = head->next;

     while(p!=NULL)

     {

         pnext = p->next;

         if(pnext == NULL)

             head->next = p;

         p->next = pre;

         pre = p;

         p = pnext;

     }

     return head;

 }

 int main(void)

 {

     linklist *mylist = NULL;

     printf("#### Creat linklist.\n");

     mylist = CreatLinklist();

     Outputlinklist(mylist);

     printf("#### Insert new node.\n");

     InsertLinklist(mylist, );

     Outputlinklist(mylist);

     printf("#### Delete exist node.\n");

     DeleteNode(mylist, );

     Outputlinklist(mylist);

     printf("#### Reverse Linklist.\n");

     Reverselinklist(mylist);

     Outputlinklist(mylist);

     printf("Handle complete!");

 }