我的时间表表程序中的任何建议

Question

I create a struct to hold the class schedule table:

struct timetable_t {
    int id;
    int weekday;
    float start_time;
    float end_time;
    int start_week;
    int end_week;
    int is_even;
    char* name;
    char* location;
};

typedef struct t_class {
    struct timetable_t t;
    struct t_class* pre;
    struct t_class* next;
}CLASS;

below is the data:

static struct timetable_t timetable[] = {
    {113172, 1, 10.10, 12.00, 3, 17, 2, "PE", "B-410"},
    {121172, 1, 14.00, 15.50, 1, 17, 2, "English", "B-101"},
    {131172, 1, 16.00, 18.00, 1, 17, 2, "Music", "B-101"},
    {141132, 1, 18.30, 20.30, 2, 13, 2, "Science", "C2-207"},
};

create double link list

CLASS* create_class(struct timetable_t* arr, int len) {
    int i;
    CLASS* head = NEW(1);
    CLASS* p = head;
    CLASS* t = NULL;
    for (i = 0; i < len; ++i) {
        t = NEW(1);
        t->t.id = arr[i].id;
        t->t.weekday = arr[i].weekday;
        t->t.start_time = arr[i].start_time;
        t->t.end_time= arr[i].end_time;
        t->t.start_week = arr[i].start_week;
        t->t.end_week = arr[i].end_week;
        t->t.is_even = arr[i].is_even;
        t->t.name = arr[i].name;
        t->t.location = arr[i].location;
        t->pre = p;
        p->next = t;
        p = p->next;
    }
    head->pre = p;
    p->next = head;
    return head;
}

Now I use a linklist double linked list to organize the data, in my program, by compare the current "hour.day" if I want to get the current class. then problems comes, is there any simple way to get the next class if current class is NULL.

Answer 1

The way I have done this is make head a global. And then provide a function that walks the list (starting at head) to get what you want. So you can count, get_next, get_next_by_value things like that.