不带表头节点的循环单向链表

来源：互联网发布：航天信息a3软件下载编辑：程序博客网时间：2024/05/12 20:59

#include<stdio.h>
#include<stdlib.h>
struct node
{
int num;
struct node * next;
};
typedef struct node Node;
typedef struct node * Link;
void create_link(Link * head)
{
*head = NULL;
}
void insert_node_head(Link *head,Link new_node)
{
Link tmp;
tmp = *head;
if(NULL == *head)
{
new_node->next = new_node;
*head = new_node;
return;
}
else
{
while(tmp->next != *head)
{
tmp = tmp->next;
}
tmp->next = new_node;
new_node->next = *head;
*head = new_node;
}
}
void display_node(Link head)
{
Link tmp;
tmp = head;
if(NULL == head)
{
printf("link is empty!\n");
return;
}
while(tmp->next != head)
{
printf("num = %d\n",tmp->num);
tmp = tmp->next;
}
printf("num = %d\n",tmp->num);
}
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;
if(*head == NULL)
{
new_node->next = new_node;
*head = new_node;
}
else
{
while(tmp->next != *head)
{
tmp = tmp->next;
}
tmp->next = new_node;
new_node->next = *head;
*head = new_node;
}
}
void makeEmpty(Link *head)
{
Link tmp;
Link head_old;
head_old = *head;
tmp = *head;
if(NULL == *head)
{
printf("Link is empty!\n");
return;
}
/*while (tmp != NULL)
{
*head = tmp->next;
free(tmp);
tmp = tmp->next;
}*/
while(tmp->next != head_old)
{
*head = (*head)->next;
free(tmp);
tmp = *head;
}
free(tmp);
*head = NULL;
}
void insert_node_mid(Link *head,Link new_node,int num)
{
Link tmp;
Link p;
tmp = *head;
p = *head;
if(NULL == *head)
{
new_node->next = new_node;
*head = new_node;
return;
}
else
{
while((num > tmp->num) &&(tmp->next != *head))
{
p = tmp;
tmp = tmp->next;
}
if(num <= tmp->num)
{
if(tmp == *head)
{
new_node->next = tmp;
*head = new_node;
}
else
{
p->next = new_node;
new_node->next = tmp;
}
}
if((num > tmp->num)&&(tmp->next == *head))
{
tmp->next = new_node;
new_node->next = *head;
}
}
}
void reverse_link(Link *head)
{
Link p1 = NULL;
Link p2 = NULL;
Link p3 = NULL;
Link old_p3 = NULL;
if(NULL == *head || (*head)->next == *head)
{
printf("No need reverse!\n");
return;
}
else
{
p3 = *head;
p2 = p3->next;
if(p2->next == *head)
{
p2->next = p3;
*head = p2;
p3->next = *head;
return;
}
p1 = p2->next;
old_p3 = p3;
while(p1->next != *head)
{
p2->next = p3;
p3 = p2;
p2 = p1;
p1= p1->next;
}
p2->next = p3;
p1->next = p2;
*head = p1;
old_p3->next = *head;
}
}
int main()
{
Link head = NULL;
Link new_node = NULL;
int i;
create_link(&head);
for(i = 0; i < 10;i++)
{
create_newnode(&new_node);
new_node->num = i;
//insert_node_mid(&head,new_node,new_node->num);
insert_node_head(&head,new_node);
//insert_node_tail(&head,new_node);
}
display_node(head);
//makeEmpty(&head);
reverse_link(&head);
display_node(head);
return 0;
}

0 0