std::ranges::adjacent_transform_view<V,F,N>::begin

From cppreference.com
Ranges library
Range adaptors
constexpr auto begin();
(1) (since C++23)
constexpr auto begin( ) const

requires ranges::range < const InnerView> &&
std::regular_invocable < const F&,

/*REPEAT*/ ( ranges::range_reference_t < const V>, N)...> ;
(2) (since C++23)

Returns an iterator to the first element of the adjacent_transform_view

Let inner_ be the underlying ranges::adjacent_view.

1) Equivalent to return /*iterator*/ < false > ( *this, inner_.begin ( ) ) ;
2) Equivalent to return /*iterator*/ < true > ( *this, inner_.begin ( ) ) ;

Parameters

(none)

Return value

Iterator to the first element.

Example

#include <ranges>
 
int main()
{
    auto sum = [](auto... args) { return (... + args); };
 
    constexpr auto view = std::views::iota(13, 1337)
                        | std::views::adjacent_transform<3>(sum);
 
    static_assert(*view.begin() == 42 and 42 == 13 + 14 + 15);
}

See also

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)