C++11 enum classes boilerplate

gistfile1.cpp

enum class dna_strand : char {
    positive = '+',
    negative = '-'
};

std::ostream& operator <<(std::ostream& out, dna_strand strand) {
    return out << static_cast<char>(strand);
}

std::istream& operator >>(std::istream& in, dna_strand& strand) {
    char ch{};
    if (not in >> ch)
        return in;
    if (ch == '+')
        strand = dna_strand::positive;
    else if (ch == '-')
        strand = dna_strand::negative;
    else
        in.setstate(std::ios::failbit);
    return in;
}