#include <cctype>
#include <climits>
#include <ios>
#include <iostream>
#include <iomanip>
#include <locale>
#include <stdexcept>

int main()
{
    try
    {
        std::locale loc;
        std::ctype<char> const &ct = std::use_facet<std::ctype<char> >(loc);
        std::ctype<wchar_t> const &wct = std::use_facet<std::ctype<wchar_t> >(loc);

        // Narrow
        std::cout << "NARROW\n";
        for (int i = 0; i < UCHAR_MAX; i++)
        {
            if (ct.is(std::ctype_base::xdigit, (char)i))
                std::cout << "\t" << (char)i << std::endl;
        }

        // wide
        std::cout << "WIDE\n";
        for (int i = 0; i < UCHAR_MAX; i++)
        {
            if (wct.is(std::ctype_base::xdigit, (wchar_t)i))
                std::cout << "\t" << (char)i << std::endl;
        }
    }
    catch(std::exception const &e)
    {
        std::cout << "EXCEPTION: " << e.what() << std::endl;
        return -1;
    }
}