iterator for 2d vector

Question

How to create iterator/s for 2d vector (a vector of vectors)?

Answer 1

Since it's 2020, I'll post an updated and easy method. Works for c++11 and above as of writing. See the following example, where elements (here: tuples of ) of 2D vector (vector of vector) is iterated to compare with another value (string query) and the function then returns first element with match, or indicate "Not found".

tuple find_serial_data( vector >> &serial,
                                        string query)
{
    for (auto& i : serial)
    {
        for (auto& j : i)
        {
            if ( get<0>(j).compare(query) == 0) return j;
        }
    }
    cout << "\n Not found";
    return make_tuple( "", 0);
}

Here is one example without the tuple thing:

string find_serial_data( vector  > &serials,
                                        string query)
{
    for (auto& i : serials)
    {
        for (auto& j : i)
        {
            if ( j.compare(query) == 0) return j;
        }
    }
    cout << "\n Not found";
    return  "";
}