list.h

//
// Created by helloqiu on 2017/3/18.
//

#ifndef LIST_LIST_H
#define LIST_LIST_H

struct list_head {
    struct list_head *next, *prev;
};

static __inline void __list_add(struct list_head *newx, struct list_head *prev, struct list_head *next) {
    next->prev = newx;
    newx->next = next;
    newx->prev = prev;
    prev->next = newx;
}

static __inline void list_add(struct list_head *newx, struct list_head *head) {
    __list_add(newx, head, head->next);
}

static __inline void list_add_tail(struct list_head *newx, struct list_head *head) {
    __list_add(newx, head->prev, head);
}

static __inline void INIT_LIST_HEAD(struct list_head *list) {
    list->next = list;
    list->prev = list;
}

static __inline struct list_head *list_get_tail(struct list_head *list) {
    if (list->next == list) {
        return list;
    } else {
        return list_get_tail(list->next);
    }
}

#define list_for_each(pos, head) \
        for (pos = (head)->next; pos != (head); pos = pos->next)

#endif //LIST_LIST_H

main.c

#include "set.h"

int main() {
    struct set a, b;
    INIT_SET(&a);
    INIT_SET(&b);
    for (int i = 0; i < 10; i++) {
        add_item(&a, i);
        add_item(&b, i + 1);
    }
    print_set(intersection(&(a), &(b)));
}

set.h

//
// Created by helloqiu on 2017/3/18.
//

#ifndef LIST_SET_H
#define LIST_SET_H

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

#define container_of(posx, type, member) \
    ((char *)posx - offsetof(type, member))

struct set {
    int value;
    struct list_head list;
};

static __inline void INIT_SET(struct set *s) {
    INIT_LIST_HEAD(&s->list);
    s->value = NULL;
}

static __inline void add_item(struct set *s, int n) {
    if (s->value == NULL) {
        s->value = n;
        return;
    } else {
        struct set *temp;
        temp = malloc(sizeof(struct set));
        INIT_SET(temp);
        temp->value = n;
        list_add(&(temp->list), &(s->list));
    }
}

static __inline void add_set(struct set *s, struct set *new_s) {
    list_add(&(new_s->list), list_get_tail(&(s->list)));
}

static __inline struct set *intersection(struct set *a, struct set *b) {
    struct set *c;
    c = malloc(sizeof(struct set));
    INIT_SET(c);
    struct set *temp_b;
    struct set *temp_a;
    struct list_head *pos_b;
    struct list_head *pos_a;
    list_for_each(pos_b, &(b->list)) {
        temp_b = (struct set *) container_of(pos_b, struct set, list);
        list_for_each(pos_a, &(a->list)) {
            temp_a = (struct set *) container_of(pos_a, struct set, list);
            if (temp_a->value == temp_b->value) {
                add_item(c, temp_a->value);
                break;
            }
        }
    }
    return c;
}

static __inline void print_set(struct set *s) {
    struct list_head *pos;
    struct set *temp;
    list_for_each(pos, &(s->list)) {
        temp = (struct set *) container_of(pos, struct set, list);
        printf("%d\n", temp->value);
    }
}

#endif //LIST_SET_H