Thread: Problem with search function within an ordered list

Do you want a search to find book titles that DON'T match your query?

You need to show some examples of what you DO want.

I want a search to find titles of books that also correspond in part to my query.

The second too?

Originally Posted by drew99

I want a search to find titles of books that also correspond in part to my query.

1) You need to look into how for() loops work...
2) You can't compare strings on the == or != token

This is the complete function:

Code:

struct libri
{
int code;
char title[MAX_TITLE_LEN];
char des[MAX_DES_LEN];
int next;
}
struct libri *start = 0;

struct libri ***search(const char title[])
{
    struct libri **books = (struct libri**) malloc(sizeof(struct libri*));
    if(!books)
    {
        puts("Ricerca interrotta");
    }
    books[0] = start;
    struct libri ***point;
    struct libri *a = (struct libri*)malloc(sizeof(struct libri));
    if(!a)
    {
        puts("Ricerca interrotta");
    }
    int s = 1;
    for(a = start; a; a = a->next)
    {
        if(strstr(a->title, title))
        {
            books = (struct libri **) realloc(books, sizeof(struct comp*) * (s + 1));
            if(!books)
            {
                puts("Ricerca non completata");
                goto ret;
            }
            point = &books;
            (*point)[s] = a;
            s++;
        }
    }
    (*point)[0]->code = s - 1;
ret:
    return point;
}

I solved the previous problems, but two remain:
- The books of the vector element 0 is equal to the element 1 (noticed when running the program)
- If you start searching an empty database the statement "(* point) [0] -> code = s - 1," returns error.

Sub word matching of a string, to all the titles ---hmmm.


I'd use strstr() on every title, to start with, as a starting point.

Originally Posted by Adak

I'd use strstr() on every title, to start with, as a starting point.

Actually, it sounds like the title has to start with the search string, not just contain it:

Originally Posted by drew99

The problem is: only if the titles of books in the database start with my search string, the function finds them (eg Title: hunting in the woods, Search string: hun).
Any suggestions?

If that's the case, then the OP needs to use strncmp(), not strstr(). However, it seems more useful to use strstr(), since many people don't consider small words like "the" and "a" when searching for a book title.