双向线性链表的实现

头文件“ls.h”

/* 双向线性链表 */#ifndef _LS_H#define _LS_H#include <sys/types.h>/* 节点 */typedef struct ListNode {int              data; /* 数据 */struct ListNode* prev; /* 前指针 */struct ListNode* next; /* 后指针 */}LIST_NODE;/* 链表 */typedef struct List {LIST_NODE* head; /* 头指针 */LIST_NODE* tail; /* 尾指针 *//*考虑用户需求，提供迭代接口*/LIST_NODE* frwd;//正向迭代指针，指向链表中任意指针，正向移动LIST_NODE* bkwd;//反向迭代指针}LIST;/* 初始化为空链表 */void list_init (LIST* list);/* 释放剩余节点并恢复到初始状态 */void list_deinit (LIST* list);/* 判断是否空 */int list_empty (LIST* list);/* 追加 */void list_append (LIST* list, int data);/* 前插 */int list_insert (LIST* list, size_t pos, int data);/* 随机访问 */int* list_at (LIST* list, size_t pos);//int*是返回位置，为了方便用户读并进行后续修改，删除等操作/* 删除 */int list_erase (LIST* list, size_t pos);/* 删除所有匹配数据 */void list_remove (LIST* list, int data);/* 清空 */void list_clear (LIST* list);/* 数量 */size_t list_size (LIST* list);//双向正向迭代器/*开始正向迭代——随机遍历（让用户可以随机迭代）*/void list_begin (LIST* list);/* 向后正向迭代 */int* list_next (LIST* list);/* 向前正向迭代 */int* list_prev (LIST* list);/* 获取正向迭代当前值 */int* list_current (LIST* list);/* 判断正向迭代是否终止 */int list_end (LIST* list);//反向迭代器/* 开始反向迭代 */void list_rbegin (LIST* list);/* 向后反向迭代 */int* list_rnext (LIST* list);/* 向前反向迭代 */int* list_rprev (LIST* list);/* 获取反向迭代当前值 */int* list_rcurrent (LIST* list);/* 判断反向迭代是否终止 */int list_rend (LIST* list);

#endif /* _LS_H */

函数具体实现过程"ls.c"

/* 双向线性链表 */#include <stdlib.h>#include "ls.h"/* 创建节点 */static LIST_NODE* create_node (int data,LIST_NODE* prev, LIST_NODE* next) {LIST_NODE* node = malloc (sizeof (LIST_NODE));node->data = data;node->prev = prev;node->next = next;return node;}/* 销毁节点 */static LIST_NODE* destroy_node (LIST_NODE* node,LIST_NODE** prev) {LIST_NODE* next = node->next;if (prev)*prev = node->prev;free (node);return next;}/* 初始化为空链表 */void list_init (LIST* list) {list->head = NULL;list->tail = NULL;}/* 释放剩余节点并恢复到初始状态 */void list_deinit (LIST* list) {while (list->head)list->head = destroy_node (list->head,NULL);list->tail = NULL;}/* 判断是否空 */int list_empty (LIST* list) {return ! list->head && ! list->tail;}/* 追加 */void list_append (LIST* list, int data) {list->tail = create_node (data,list->tail,NULL);if (list->tail->prev)list->tail->prev->next = list->tail;elselist->head = list->tail;}/* 前插 */int list_insert (LIST* list, size_t pos, int data) {LIST_NODE* find = NULL;for (find = list->head; find; find = find->next)if (! pos--) {LIST_NODE* node = create_node (data,find->prev, find);if (node->prev)node->prev->next = node;elselist->head = node;node->next->prev = node;return 1;}return 0; //插入失败}/* 随机访问 */int* list_at (LIST* list, size_t pos) {LIST_NODE* find = NULL;for (find = list->head; find; find = find->next)if (! pos--)return &find->data;return NULL;}/* 删除 */int list_erase (LIST* list, size_t pos) {LIST_NODE* find = NULL;for (find = list->head; find; find = find->next)if (! pos--) {LIST_NODE* prev = NULL;LIST_NODE* next = destroy_node (find,&prev);if (prev)prev->next = next;elselist->head = next;if (next)next->prev = prev;elselist->tail = prev;return 1;}return 0;}/* 删除所有匹配数据 */void list_remove (LIST* list, int data) {LIST_NODE* find = NULL, *next = NULL;for (find = list->head; find; find = next) {next = find->next;if (find->data == data) {LIST_NODE* prev = NULL;LIST_NODE* next = destroy_node (find,&prev);if (prev)prev->next = next;elselist->head = next;if (next)next->prev = prev;elselist->tail = prev;}}}/* 清空 */void list_clear (LIST* list) {list_deinit (list);}/* 数量 */size_t list_size (LIST* list) {size_t size = 0;LIST_NODE* node = NULL;for (node = list->head; node; node = node->next)++size;return size;}/* 开始正向迭代 */void list_begin (LIST* list) {list->frwd = list->head;}/* 向后正向迭代 */int* list_next (LIST* list) {int* data = &list->frwd->data;list->frwd = list->frwd->next;return data;}/* 向前正向迭代 */int* list_prev (LIST* list) {int* data = &list->frwd->data;list->frwd = list->frwd->prev;return data;}/* 获取正向迭代当前值 */int* list_current (LIST* list) {return &list->frwd->data;}/* 判断正向迭代是否终止 */int list_end (LIST* list) {return ! list->frwd;}/* 开始反向迭代 ，与正向迭代的反向迭代方向相反*/ void list_rbegin (LIST* list) {list->bkwd = list->tail;}/* 向后反向迭代 */int* list_rnext (LIST* list) {int* data = &list->bkwd->data;list->bkwd = list->bkwd->prev;return data;}/* 向前反向迭代 */int* list_rprev (LIST* list) {int* data = &list->bkwd->data;list->bkwd = list->bkwd->next;return data;}/* 获取反向迭代当前值 */int* list_rcurrent (LIST* list) {return &list->bkwd->data;}/* 判断反向迭代是否终止 */int list_rend (LIST* list) {return ! list->bkwd;}

测试用例"ls_test.c"

/* 双向线性链表 */#include <stdio.h>#include "ls.h"/* 测试用例 */int main (void) {LIST list;list_init (&list);list_append (&list, 10);list_append (&list, 30);list_append (&list, 50);list_insert (&list, 1, 20);list_insert (&list, 3, 40);for (list_begin (&list); ! list_end (&list);list_next (&list))printf ("%d ", ++*list_current (&list));printf ("\n");list_append (&list, 41);list_append (&list, 41);list_begin (&list);while (! list_end (&list))printf ("%d ", *list_next (&list));printf ("\n");list_erase (&list, 1);list_remove (&list, 41);list_rbegin (&list);while (! list_rend (&list))printf ("%d ", *list_rnext (&list));printf ("\n");size_t pos, size = list_size (&list);for (pos = 0; pos < size; ++pos)printf ("%d ", --*list_at (&list, pos));printf ("\n");list_clear (&list);printf ("%d, %d\n", list_empty (&list),list_size (&list));list_deinit (&list);return 0;}