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std::ranges::adjacent_view<V,N>::begin

constexpr auto begin() requires (!__SimpleView<V>);
 (1) (since C++23) 
constexpr auto begin() const requires ranges::range<const V>;
 (2) (since C++23)

Returns an iterator to the first element of the adjacent_view.

Let base_ be the underlying view.

1) Equivalent to return /*iterator*/<false>(ranges::begin(base_), ranges::end(base_));.
2) Equivalent to return /*iterator*/<true>(ranges::begin(base_), ranges::end(base_));.

Parameters

(none).

Return value

Iterator to the first element.

Example

A link to test: Compiler Explorer/g++-13.

#include <tuple>
#include <ranges>
#include <type_traits>
 
int main()
{
    constexpr static auto v = {'A', 'B', 'C', 'D', 'E'};
 
    constexpr auto view = std::views::adjacent<3>(v);
 
    constexpr auto tuple = *view.begin();
 
    static_assert(
        std::is_same_v<
            decltype(tuple),
            const std::tuple<char const&, char const&, char const&>
    >);
 
    static_assert(
        std::get<0>(tuple) == 'A' and
        std::get<1>(tuple) == 'B' and
        std::get<2>(tuple) == 'C'
    );
}

See also

(C++23)
 returns an iterator or a sentinel to the end
(public member function)
(C++20)
 returns an iterator to the beginning of a range
(customization point object)

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