Question

I was wondering, I normally use std::string for my code, but when you are passing a string in a parameter for a simply comparison, is it better to just use a literal?

Consider this function:

bool Message::hasTag(string tag)
{
    for(Uint tagIndex = 0; tagIndex < m_tags.size();tagIndex++)
    {
        if(m_tags[tagIndex] == tag)
            return 0;
    }

    return 1;
}

Despite the fact that the property it is making a comparison with is a vector, and whatever uses this function will probably pass strings to it, would it still be better to use a const char* to avoid creating a new string that will be used like a string literal anyway?

Answer 1

If you want to use classes, the best approach here is a const reference:

bool Message::hasTag(const string& tag);

That way, redudant copying can be minimized and it’s made clear that the method doesn’t intend to modify the argument. I think a clever compiler can emit pretty good code for the case when this is called with a string literal.

Passing a character pointer requires you to use strcmp() to compare, since if you start comparing pointers directly using ==, there will be … trouble.