#include <iostream>

#include <boost/lexical_cast.hpp>

enum class Foo
{
    bar,
    baz
};

std::ostream &operator <<(std::ostream &out, Foo f)
{
    switch (f)
    {
    case Foo::bar: out << "bar"; break;
    case Foo::baz: out << "baz"; break;
    default: out << "(invalid)"; break;
    }
    return out;
}

int main()
{
    auto s = boost::lexical_cast<std::string>(Foo::baz);
    std::cout << s << '\n';
}