这篇文章写的是双向循环链表,这也是个非常经典的数据结构,我们在看 Linux 内核代码时就经常会遇到它。比如,在Linux的内核中实现进程描述符,使用的就是双向循环链表,因为它使用起来很方便,每个节点不只是有 data 字段,还有 prev , next 字段,对于向前和向后查找相应的节点很方便,下面贴出实现代码,仍然是很简单的操作,且没有过多的错误控制:
头文件:
/*
* dlut_dclist.h
*
* Created on: 2014年1月13日
* Author: DLUTBruceZhang
*/
#ifndef DLUT_DCLIST_H_
#define DLUT_DCLIST_H_
typedef int need;
typedef struct _dclist
{
need data;
struct _dclist *next;
struct _dclist *prev;
}dclist;
dclist * dlut_dclist_create();
void dlut_dclist_insert_to_head(dclist *, need);
void dlut_dclist_insert_to_tail(dclist *, need);
void dlut_dclist_delete_the_head(dclist *);
void dlut_dclist_delete_the_tail(dclist *);
void dlut_dclist_delete_the_data(dclist *, need);
need dlut_dclist_get_the_head(dclist *);
need dlut_dclist_get_the_tail(dclist *);
void dlut_dclist_print_the_dclist(dclist *);
void dlut_dclist_delete_the_dclist(dclist *);
#endif /* DLUT_DCLIST_H_ */
C文件:
/*
* dlut_dclist.c
*
* Created on: 2014年1月13日
* Author: DLUTBruceZhang
*/
#include "dlut_dclist.h"
#include <stdlib.h>
#include <stdio.h>
dclist * dlut_dclist_create()
{
dclist *head;
head = (dclist *)malloc(sizeof(dclist));
if (!head)
return NULL;
head -> data = 0;
head -> next = head;
head -> prev = head;
return head;
}
void dlut_dclist_insert_to_head(dclist *head, need data)
{
dclist *new_node;
new_node = (dclist *)malloc(sizeof(dclist));
if (!new_node)
return;
new_node -> data = data;
new_node -> next = head -> next;
head -> next -> prev = new_node;
head -> next = new_node;
new_node -> prev = head;
head -> data += 1;
return;
}
void dlut_dclist_insert_to_tail(dclist *head, need data)
{
dclist *new_node;
new_node = (dclist *)malloc(sizeof(dclist));
if (!new_node)
return;
new_node -> data = data;
dclist *_head = head;
while (_head -> next != head)
_head = _head -> next;
new_node -> next = head;
head -> prev = new_node;
new_node -> prev = _head;
_head -> next = new_node;
head -> data += 1;
return;
}
void dlut_dclist_delete_the_head(dclist *head)
{
dclist *old_node;
if (head -> next == head)
return;
old_node = head -> next;
head -> next -> next -> prev = head;
head -> next = head -> next -> next;
head -> data -= 1;
free(old_node);
return;
}
void dlut_dclist_delete_the_tail(dclist *head)
{
dclist *old_node;
if (head -> next == head)
return;
dclist *_head = head;
while (_head -> next != head)
_head = _head -> next;
old_node = _head;
_head -> prev -> next = head;
head -> prev = _head -> prev;
head -> data -= 1;
free(old_node);
return;
}
void dlut_dclist_delete_the_data(dclist *head, need data)
{
if (head -> next == head)
return;
dclist *_head = head;
while (_head -> data != data && _head -> next != head)
_head = _head -> next;
if (_head -> data == data)
{
_head -> prev -> next = _head -> next;
_head -> next -> prev = _head -> prev;
head -> data -= 1;
}
return;
}
need dlut_dclist_get_the_head(dclist *head)
{
return head -> data == 0 ? -1 : head -> next -> data;
}
need dlut_dclist_get_the_tail(dclist *head)
{
return head -> data == 0 ? -1 : head -> prev -> data;
}
void dlut_dclist_print_the_dclist(dclist *head)
{
dclist *_head = head -> next;
while (_head != head)
{
printf("%d ", _head -> data);
_head = _head -> next;
}
printf("\n");
return;
}
void dlut_dclist_delete_the_dclist(dclist *head)
{
while (head -> next != head)
dlut_dclist_delete_the_head(head);
free(head);
return;
}