pattern do_pos_format() const;The protected virtual member function returns a locale-specific rule for determining how to generate a monetary output
field for a positive amount. (It also determines how to match the components of a monetary input field.) The encoding is
the same as for do_neg_format.
The template version of moneypunct<E, Intl> returns {money_base::symbol, money_base::sign,
money_base::value, money_base::none}.