[view.interface.members]

🔗

constexpr decltype(auto) front() requires forward_range<D>;
constexpr decltype(auto) front() const requires forward_range<const D>;

Effects: Equivalent to: return *ranges::begin(derived();

🔗

constexpr decltype(auto) back() requires bidirectional_range<D> && common_range<D>;
constexpr decltype(auto) back() const
  requires bidirectional_range<const D> && common_range<const D>;

Effects: Equivalent to: return *ranges::prev(ranges::end(derived();

25 Ranges library [ranges]

25.5 Range utilities [range.utility]

25.5.3 View interface [view.interface]

25.5.3.2 Members [view.interface.members]