Converting from a std::string to bool

Question

What is the best way to convert a std::string to bool? I am calling a function that returns either \"0\" or \"1\", and I need a clean solution for turning this into a boole

Answer 1

You could always wrap the returned string in a class that handles the concept of boolean strings:

class BoolString : public string
{
public:
    BoolString(string const &s)
    :   string(s)
    {
        if (s != "0" && s != "1")
        {
            throw invalid_argument(s);
        }
    }

    operator bool()
    {
        return *this == "1";
    }
}

Call something like this:

BoolString bs(func_that_returns_string());
if (bs) ...;
else ...;

Which will throw invalid_argument if the rule about "0" and "1" is violated.