带头结点的双向循环链表C语言

/*****************************************************
Author：Simon_Kly    Version:0.1    Date: 20170520
Description：带头结点的双向循环链表
Mail: degaullekong@gmail.com
Funcion List: 
*****************************************************/

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

typedef struct node
{
    int data;
    struct node *prior, *next;
}Node, *Link;

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

/*创建链表*/
void create_link(Link * head)
{
    *head = (Link)malloc(sizeof(Node));

    is_malloc_ok(*head);

    (*head)->next = (*head)->prior = *head;//让其指向自己
}

/*创建节点*/
void create_node(Link * new_node)
{
    *new_node = (Link)malloc(sizeof(Node));
    is_malloc_ok(*new_node);
}

/*插入节点(头插)*/
void insert_node_head(Link head, Link new_node)
{
    new_node->prior = head;
    new_node->next = (head)->next;
    (head)->next->prior = new_node;
    (head)->next = new_node;
}


/*插入节点(尾插)*/
void insert_node(Link * head, Link new_node)
{
    Link p = NULL;

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

    new_node->prior = p;
    new_node->next = p->next;
    p->next->prior = new_node;
    p->next = new_node;
}

/*输出链表*/
void out_link(Link head)
{
    Link p = NULL;
#if 0
    if (head->next == head)
    {
        printf("link is empty\n");
        return ;
    }
#endif

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

    p = (head)->next;

    while (p != head)
    {
        printf("%d\n", p->data);
        p = p->next;
    }
    putchar(10);
}

/*变成空链*/
void make_empty(Link * head)
{
    Link p = NULL;

    p = (*head)->next;

    while (*head != (*head)->next)
    {
        (*head)->next = p->next;//head移动
        free(p);//释放head之前的节点
        p = (*head)->next;
    }
}

/*释放链表*/
void release_link(Link * head)
{
    make_empty(head);

    free(*head);

    *head = NULL;
}

/*删除节点*/
void delete_node(Link * head, int data)
{
    Link p = NULL;

    p = (*head)->next;

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

    /*非空链*/
    while (p != *head && p->data != data)
    {
        p = p->next;//找那个节点
    }

    if (p == *head)//找一圈没找到
    {
        printf("No such node!\n");
        return ;
    }
    else//找到并改变指向
    {
        p->prior->next = p->next;
        p->next->prior = p->prior;
        
        free(p);
    }
}

void insert_node_seq(Link * head, Link new_node)
{
    Link p = NULL;

    p = (*head);

    while (p->next != *head && new_node->data < p->next->data)//找到该位置的前一个位置
    {
        p = p->next;
    }
#if 0
    if (p == *head)//找到尾部
    {
        new_node->prior = p->prior;
        new_node->next = p;
        p->prior->next = new_node;
        p->prior = new_node;
        return ;
    }
#endif
    new_node->prior = p;
    new_node->next = p->next;
    p->next->prior = new_node;
    p->next = new_node;

}

int main()
{
    int i;
    Link head = NULL;
    Link new_node = NULL;
    create_link(&head);
    
    out_link(head);
    
    for (i = 0; i < 10; i++)
    {
        create_node(&new_node);
        new_node->data = i + 1;
    //    insert_node(&head, new_node);
        insert_node_head(head, new_node);
    }
    
    out_link(head);
    
#if 1
    printf("please input i\n");
    scanf("%d", &i);
    putchar(10);
    create_node(&new_node);
    new_node->data = i;
    insert_node_seq(&head, new_node);
    out_link(head);
#endif
    
#if 0
    delete_node(&head, 2);
    out_link(head);
#endif
    release_link(&head);
    out_link(head);
    return 0;
}