简单的通用链表实现

来源：互联网发布：金石造价格软件编辑：程序博客网时间：2024/05/12 22:27

最近项目需要用到链表，并且是建立三个不同的专用链表，为了对代码加以简化，特采用通用链表来实现代码功能！

本链表是在linux下运行的，因此含有部分系统函数。

本人对指针理解较为粗糙，不能保证代码正确性，仅作自己总结而用！

代码未加封装，只有简单的实现函数。

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <stdbool.h>typedef struct listnode{    struct listnode *next;    struct listnode *prev;    void            *data;}List;//新建链表头List *createNode(void){    List *head = (List *)malloc(sizeof(List));    if(NULL == head)    {        printf("Usage : malloc error !\n");        return NULL;    }    head->next = head->prev = head;    return head;}//尾插法List *tailInsert(List *head, void *data){    List *node = (List *)malloc(sizeof(List));    if(NULL == node)    {        printf("Usage : malloc error !\n");        return NULL;    }    node->data = data;    head->prev->next = node;    node->prev = head->prev;    head->prev = node;    node->next = head;    return head;}//摧毁链表void destroyList(List **head){    List *tmp = NULL;    List *next = NULL;    if((*head)->next == *head)    {        return;    }    for(tmp=*head; tmp->next!=*head; tmp=next)    {        next = tmp->next;        free(tmp);    }    *head = NULL;}//按compare函数来检索链表节点List *searchList(List *head, void *key, bool (*compare)(void *, void *)){    List *ptr = head;    while(ptr->next != head)    {        ptr = ptr->next;        if(compare(ptr->data, key))        {            return ptr;        }    }    return NULL;}//删除compare函数检索到的节点List *deleteList(List *head, void *key, bool(*compare)(void *, void*)){    List *ptr = head;    while(ptr->next != head)    {        ptr = ptr->next;        if(compare(ptr->data, key))        {            ptr->prev->next = ptr->next;            ptr->next->prev = ptr->prev;            free(ptr);            break;        }    }    return head;}//打印链表void printList(List *head, void (*print)(void *)){    List *ptr = head;    while(ptr->next != head)    {        ptr = ptr->next;        print(ptr->data);    }}//把链表存入文件void saveList(List *head, const char *filename, size_t size){    int fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0777);    if(-1 == fd)    {        printf("Usage : open error !\n");        return;    }    List *ptr = head;    while(ptr->next != head)    {        ptr = ptr->next;        write(fd, ptr->data, size);    }    close(fd);    destroyList(&head);}//从文件读入链表List *readList(const char *filename, size_t size){    int fd, ret;    List *head = createNode();    if(access(filename, F_OK) != 0)    {        close(open(filename, O_CREAT | O_APPEND, 0777));    }    fd = open(filename, O_RDONLY);    if(-1 == fd)    {        printf("Usage : open error !\n");        return NULL;    }    while(1)    {        void *data;        data = malloc(size);        ret = read(fd, data, size);        if(0 == ret)        {            break;        }        tailInsert(head, data);    }    close(fd);    return head;}

简单测试：

typedef struct action{    char name[20];    int id;}action_t;//比较函数bool compare(void *data, void *key){    action_t *act = (action_t *)data;    int id = (int)key;    if(act->id == id)    {        return true;    }    return false;}//打印函数void print(void *data){    action_t *act = (action_t *)data;    printf("id   = %d\t", act->id);    printf("name = %s\n", act->name);}int main(void){    char *filename = "action.txt";    action_t test1 = {"zhao", 1};    action_t test2 = {"qian", 2};    action_t test3 = {"yang", 3};    action_t test4 = {"ling", 4};    action_t test5 = {"zhou", 5};    List *head = createNode();    tailInsert(head, (void *)(&test1));    tailInsert(head, (void *)(&test2));    tailInsert(head, (void *)(&test3));    tailInsert(head, (void *)(&test4));    tailInsert(head, (void *)(&test5));    printList(head, print);    //存入文件    saveList(head, filename, sizeof(action_t));    //从文件读取    List *list = readList(filename, sizeof(action_t));    if(deleteList(list, (void *)1, compare))    {        printf("删除id为1的节点，成功则打印！\n");    }    //检验是否删除成功    printList(list, print);    return 0;}

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