c语言单向链表的实现

1. slist.h

#ifndef _SLIST_H
#define _SLIST_H

typedef struct _slist_node
{
    struct _slist_node *p_next; /* 指向下一个结点的指针 */
}slist_node_t;

typedef slist_node_t slist_head_t;
typedef int (*slist_node_process_t)(void *p_arg, slist_node_t *p_node);

int slist_init(slist_head_t *p_head);
int slist_add(slist_head_t *p_head, slist_node_t *p_pos, slist_node_t *p_node);
int slist_add_tail(slist_head_t *p_head, slist_node_t *p_node);
int slist_add_head(slist_head_t *p_head, slist_node_t *p_node);
int slist_del(slist_head_t *p_head, slist_node_t *p_node);

slist_node_t *slist_prev_get(slist_head_t *p_head, slist_node_t *p_pos);
slist_node_t *slist_next_get(slist_head_t *p_head, slist_node_t *p_pos);
slist_node_t *slist_tail_get(slist_head_t *p_head);
slist_node_t *slist_begin_get(slist_head_t *p_head);
slist_node_t *slist_end_get (slist_head_t *p_head);
int slist_foreach(slist_head_t *p_head,
                slist_node_process_t pfn_node_process,
                void *p_arg);

#endif

2. slist.c

#include "slist.h"
#include <stdlib.h>

int slist_init(slist_head_t *p_head)
{
    if (p_head == NULL)
    {
        return -1;
    }
    p_head->p_next = NULL;
    return 0;
}

int slist_add(slist_head_t *p_head, slist_node_t *p_pos, slist_node_t *p_node)
{
    p_node->p_next = p_pos->p_next;
    p_pos->p_next = p_node;
    return 0;
}

int slist_add_tail(slist_head_t *p_head, slist_node_t *p_node)
{
    slist_node_t *p_tmp = slist_tail_get(p_head); /* 找到尾结点 */
    return slist_add(p_head, p_tmp, p_node); /* 添加结点至尾结点之后 */
}

int slist_add_head(slist_head_t *p_head, slist_node_t *p_node)
{
    return slist_add(p_head, p_head, p_node); /* 添加结点至头结点之后 */
}

int slist_del(slist_head_t *p_head, slist_node_t *p_node)
{
    slist_node_t *p_prev = slist_prev_get(p_head, p_node); /* 找到待删除结点的上一个结点 */
    if (p_prev) 
    {
        p_prev->p_next = p_node->p_next;
        p_node->p_next = NULL;
        return 0;
    }
    return -1;
}

slist_node_t *slist_prev_get(slist_head_t *p_head, slist_node_t *p_pos)
{
    slist_node_t *p_tmp = p_head;
    while ((p_tmp != NULL) && (p_tmp->p_next != p_pos))
    {
        p_tmp = p_tmp->p_next;
    }
    return p_tmp;    
}

slist_node_t *slist_next_get(slist_head_t *p_head, slist_node_t *p_pos)
{
    if (p_pos) 
    {
        return p_pos->p_next;
    }
    return NULL;
}

slist_node_t *slist_tail_get(slist_head_t *p_head)
{
    return slist_prev_get(p_head, NULL);
}

slist_node_t *slist_begin_get(slist_head_t *p_head)
{
    return slist_next_get(p_head, p_head);
}

slist_node_t *slist_end_get (slist_head_t *p_head)
{
    return NULL;
}

int slist_foreach(slist_head_t *p_head,
                  slist_node_process_t pfn_node_process,
                  void *p_arg)
{
    slist_node_t *p_tmp, *p_end;
    int ret;

    if ((p_head == NULL) || (pfn_node_process == NULL))
    {
        return -1;
    }
    p_tmp = slist_begin_get(p_head);
    p_end = slist_end_get(p_head);
    while (p_tmp != p_end)
    {
        ret = pfn_node_process(p_arg, p_tmp);
        if (ret < 0) 
            return ret; /* 不再继续遍历 */
        p_tmp = slist_next_get(p_head, p_tmp); /* 继续下一个结点 */
    }
    return 0;
}

3. demo

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "slist.h"

typedef struct _student
{
    char name[10];
    char sex;
    float height, weight;
}student_t;

typedef struct _slist_student
{
    slist_node_t node;
    student_t student;
}slist_student_t;

int student_info_read (student_t *p_student) /* 读取学生记录，随机产生，仅供测试 */
{
    int i;

    for (i = 0; i < 9; i++) 
    { /* 随机名字，由'A'~'Z'组成 */
        p_student->name[i] = (rand() % ('z' - 'a')) + 'a';
    }
    p_student->name[i]= '';
    p_student->sex = (rand() & 0x01) ? 'F' : 'M'; /* 随机性别 */
    p_student->height = (float)rand() / rand();
    p_student->weight = (float)rand() / rand();
    return 0;
}

int list_node_process (void *p_arg, slist_node_t *p_node)
{
    student_t *p_s = &(((slist_student_t *)p_node)->student);
    printf("%s : %c %.2f %.2f
", p_s->name, p_s->sex, p_s->height, p_s->weight);
    return 0;
}

int main(int argc, char *argv[])
{
    slist_head_t head;
    slist_student_t s1, s2, s3, s4, s5;
    srand(time(NULL));
    slist_init(&head);

    student_info_read(&s1.student);
    student_info_read(&s2.student);
    student_info_read(&s3.student);
    student_info_read(&s4.student);
    student_info_read(&s5.student);

    slist_add_head(&head, &s1.node);
    slist_add_head(&head, &s2.node);
    slist_add_head(&head, &s3.node);
    slist_add_head(&head, &s4.node);
    slist_add_head(&head, &s5.node);

    slist_foreach(&head, list_node_process, NULL); /* 遍历链表，用户参数为NULL */

    return 0;
}