Non-members

• operator+ taking 2 args, returning concatenation: overloaded for 5 combinations of std::string and char*

• Comparison operators compare two std::strings or char*

• Overloaded combinations:

      operator==      return lhs.compare( rhs ) == 0;
      operator!=      return lhs.compare( rhs ) != 0;
      operator<       return lhs.compare( rhs ) < 0;
      operator>       return lhs.compare( rhs ) > 0;
      operator<=      return lhs.compare( rhs ) <= 0;
      operator>=      return lhs.compare( rhs ) >= 0;