why std::string is not implicitly converted to bool

Question

Is there a reason why in c++ std::string is not implicitly converted to bool? For example

std::string s = \"\"
if (s) { /* s in not empty */ }
         


        

Answer 1

The closest thing to what you (and I) want, that I've been able to find, is the following.

You can define the ! operator on std::string's like so:

bool operator!(const std::string& s)
{
    return s.empty();
}

This allows you to do:

std::string s;
if (!s)             // if |s| is empty

And using a simple negation, you can do:

if (!!s)            // if |s| is not empty

That's a little awkward, but the question is, how badly do you want to avoid extra characters? !strcmp(...) is awkward, too, but we still functioned and got used to it, and many of us preferred it because it was faster than typing strcmp(...) == 0.

If anyone discovers a way to do if (s), in C++, please let us know.