...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
// In header: <boost/pfr/tuple_size.hpp> constexpr std::size_t tuple_size_v;
tuple_size_v is a template variable that contains fields count in a T and works for any T that satisfies simple aggregate .
std::array<int, boost::pfr::tuple_size_v<my_structure> > a;