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来源：互联网发布：育碧优化好ea不坑钱编辑：程序博客网时间：2024/05/10 21:16

链表表头循环

#include <stdio.h>

#include <stdlib.h>

struct node
{
   int num;
   struct node * next;
};

typedef struct node Node;
typedef struct node * Link;

void create_newnode(Link *new_node);

void create_link(Link * head)
{
   create_newnode(head);
   (*head)->next = *head;
}

void insert_node_head(Link * head,Link new_node)
{
    new_node->next = (*head)->next;
   (*head)->next = new_node;
}

void display_node(Link head)
{
   Link tmp;
   tmp = head->next;

   if(tmp == head)
   {
       printf("the link is emply!\n");
   }

   while(tmp != head)
   {
       printf("num = %d\n",tmp->num);
       tmp = tmp->next;
   }
}

void is_malloc_ok(Link new_node)
{
     if(new_node == NULL)
   {
       printf("malloc error!\n");
       exit(-1);
   }
}

void create_newnode(Link * new_node)
{
   *new_node = (Link) malloc(sizeof(Node));
   is_malloc_ok(*new_node);
}

void insert_node_tail(Link *head,Link new_node)
{
    Link tmp;

   tmp = (*head)->next;

   while(tmp->next != *head)
   {
       tmp = tmp->next;
   }
   tmp->next = new_node;
   new_node->next = *head;
}

void insert_node_mid(Link *head,Link new_node,int num)
{
    Link tmp;
   Link p;
   tmp = (*head)->next;

   if(NULL == (*head)->next)
   {
       new_node->next = NULL;
       (*head)->next = new_node;
       return;
   }
   else
   {
       while(tmp->num < num && tmp->next != NULL)
       {
           p =tmp;
            tmp = tmp->next;
       }
        if(tmp->next != NULL)
       {
            new_node->next = tmp;
           p->next = new_node;
       }
       else
       {
           if(tmp->num < num)
           {
               new_node->next = NULL;
               tmp->next = new_node;
           }
           else
           {
               p->next = new_node;
               new_node->next = tmp;
           }
       }
   }
}

void delete_node(Link *head,int num)
{
   Link tmp;
   Link p;
   tmp = p = *head;

   if(NULL == *head)
   {
       printf("link is empty!\n");
       return;
   }

   while(tmp->num != num && tmp->next != NULL)
   {
       p = tmp;
       tmp = tmp->next;
   }

   if(tmp->num == num)
   {
        if(tmp == *head)
       {
            *head = tmp->next;
           free(tmp);
       }
       else
       {
           p->next = tmp->next;
           free(tmp);
       }
   }
   else
   {
       printf("no such node!\n");
   }
}

void release(Link *head)
{
   Link tmp = NULL;

   tmp = (*head)->next;

   while(tmp != *head)
   {
       (*head)->next = tmp->next;
       free(tmp);
       tmp = (*head)->next;
   }
}

void revers_link(Link *head)
{
   Link p1;
   Link p2;
   Link p3;

   p3 = *head;

   if(*head == NULL)
   {
       printf("the link is empty!\n");
       return;
   }
   if(p3->next == NULL)
   {
       printf("this link has only one element!\n");
       return;
   }

   p2 = p3->next;

   if(p2->next == NULL)
   {
       p3->next = NULL;
       *head =p2;
       return;
   }

   p1 = p2->next;

   while(p1->next != NULL)
   {
       p2->next = p3;
       p3 = p2;
       p2 = p1;
       p1 = p1->next;
   }
   p2->next = p3;
   p1->next = p2;
   (*head)->next = NULL;
   *head = p1;
}

int main()
{
    Link head = NULL;
    Link new_node = NULL;
    int i;
   int num;

   create_link(&head);

   for(i = 0; i < 10;i++)
   {
        create_newnode(&new_node);
       new_node->num = i;
//       insert_node_head(&head,new_node);
       insert_node_tail(&head,new_node);
   }

//   printf("please input a num!\n");
//   scanf("%d",&num);

//   create_newnode(&new_node);
//   new_node->num = num;

//   insert_node_mid(&head,new_node,num);

//   delete_node(&head,num);

   display_node(head);

//   revers_link(&head);

   release(&head);

   display_node(head);
    return 0;
}

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