xieite::big_int<Uint>::big_int()

template<std::integral Int = UInt>
[[nodiscard]] explicit(false) constexpr big_int(Int x = 0) noexcept;

template<typename OtherUInt>
[[nodiscard]] explicit constexpr big_int(const xieite::big_int<OtherUInt>& x) noexcept;

template<std::ranges::input_range Range>
requires(std::same_as<UInt, std::ranges::range_value_t<Range>>)
[[nodiscard]] explicit constexpr big_int(Range&& range, bool neg = false) noexcept;

[[nodiscard]] explicit constexpr big_int(std::string_view strv, xieite::ssize_t radix = 10, const xieite::number_str_config& config = {}) noexcept;

static_assert(xieite::big_int("FF", 16) == 255);