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std::ranges::slide_view<V>::begin

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< cpp‎ | ranges‎ | slide view
 
 
Ranges library
 
std::ranges::slide_view
slide_view::begin
Member functions
Non-member functions
Member functions
Non-member functions
 
constexpr auto begin()
    requires (!(/*simple-view*/<V> && /*slide-caches-nothing*/<const V>));
(1) (since C++23)
constexpr auto begin() const
    requires /*slide-caches-nothing*/<const V>;
(2) (since C++23)

Returns an iterator to the first element of the slide_view.

1) If V models slide-caches-first , equivalent to

return iterator <false>(ranges::begin (base_ ),
                       ranges::next (ranges::begin (base_ ), n_  - 1, ranges::end (base_ )),
                       n_ );

Otherwise, equivalent to return iterator <false>(ranges::begin (base_ ), n_ );.
If V models slide-caches-first this function caches the result within the cached_begin_ for use on subsequent calls. This is necessary to provide the amortized constant-time complexity required by the range.
2) Equivalent to return iterator <true>(ranges::begin (base_ ), n_ );.

[edit] Parameters

(none)

[edit] Return value

An iterator to the first element of slide_view, which points to the n_ -sized subrange of the underlying view type: V for overload (1) or const V for overload (2).

[edit] Example

Run this code
#include <iostream>
#include <ranges>
#include <string_view>
using namespace std::literals;
 
int main()
{
 static constexpr auto source = {"∀x"sv, "∃y"sv, "ε"sv, "δ"sv};
 auto view{std::ranges::slide_view (source, 2)};
 const auto subrange{*(view.begin())};
 for (std::string_view const s : subrange)
 std::cout << s << ' ';
 std::cout << '\n';
}

Output:

∀x ∃y

[edit] See also

returns an iterator or a sentinel to the end
(public member function) [edit]
(C++23)
compares a sentinel with an iterator returned from slide_view::begin
(function) [edit]
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