Question

Trying to make a simple program to catalogue books. Something like this, for example:

struct book{
    string author;
    string title;
    int catalogNumber;
}

Ultimately, I want to be able to do title searches based on a range. So the user could specify to display results of books where the title begins with “aa” though “be”. Ideally, the search average case would be logarithmic.

Is there something in the STL that could help me? Otherwise, what is the best way to go about this?

Thanks!

Answer 1

You can store them in an std::set, and use std::lower_bound and std::upper_bound to find a range (and yes, that should be logarithmic). To do that, you’ll need to define operator< to operate on just the field(s) you care about (title, in this case).

If you’re (virtually) always treating the title as the key, you might prefer to use an std::map<std::string, info>, with info defined like:

struct info { 
     string author;
     int catalogNumber;

     info(string a, int c) : author(a), catalogNumber(c) {}
};

This makes a few operations a little easier, such as:

books["Moby Dick"] = info("Herman Melville", 1234);

If you want to support searching by title or author (for example) consider using something like a Boost bimap or multi_index.

For what it’s worth, I’d also give serious thought to using a string instead of an int for the catalog number. Almost none of the standard numbering systems (e.g., Dewey decimal, library of congress, ISBN) will store very nicely in an int.