25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.24 Enumerate view [range.enumerate]

25.7.24.2 Class template enumerate_view [range.enumerate.view]

namespace std::ranges { template<view V> requires range-with-movable-references<V> class enumerate_view : public view_interface<enumerate_view<V>> { V base_ = V(); // exposition only // [range.enumerate.iterator], class template enumerate_view::iterator template<bool Const> class iterator; // exposition only // [range.enumerate.sentinel], class template enumerate_view::sentinel template<bool Const> class sentinel; // exposition only public: constexpr enumerate_view() requires default_initializable<V> = default; constexpr explicit enumerate_view(V base); constexpr auto begin() requires (!simple-view<V>) { return iterator<false>(ranges::begin(base_), 0); } constexpr auto begin() const requires range-with-movable-references<const V> { return iterator<true>(ranges::begin(base_), 0); } constexpr auto end() requires (!simple-view<V>) { if constexpr (forward_range<V> && common_range<V> && sized_range<V>) return iterator<false>(ranges::end(base_), ranges::distance(base_)); else return sentinel<false>(ranges::end(base_)); } constexpr auto end() const requires range-with-movable-references<const V> { if constexpr (forward_range<const V> && common_range<const V> && sized_range<const V>) return iterator<true>(ranges::end(base_), ranges::distance(base_)); else return sentinel<true>(ranges::end(base_)); } constexpr auto size() requires sized_range<V> { return ranges::size(base_); } constexpr auto size() const requires sized_range<const V> { return ranges::size(base_); } constexpr auto reserve_hint() requires approximately_sized_range<V> { return ranges::reserve_hint(base_); } constexpr auto reserve_hint() const requires approximately_sized_range<const V> { return ranges::reserve_hint(base_); } constexpr V base() const & requires copy_constructible<V> { return base_; } constexpr V base() && { return std::move(base_); } }; template<class R> enumerate_view(R&&) -> enumerate_view<views::all_t<R>>; }

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constexpr explicit enumerate_view(V base);

Effects: Initializes base_ with std::move(base).