std::ranges::slide_view<V>::begin
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< cpp | ranges | slide view
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_
);
If V models
__slide_caches_first
this function caches the result within the slide_view::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_);.
Parameters
(none)
Return value
An iterator to the first element of slide_view
, which points to the n_
-sized subrange of the possibly const-qualified underlying view type – V for overload (1) or const V for overload (2).
Example
A link to test: Compiler Explorer
Run this code
#include <ranges> #include <iostream> #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 << ' '; }
Output:
∀x ∃y
See also
(C++23) |
returns an iterator or a sentinel to the end (public member function) |
(C++23) |
compares a sentinel with an iterator returned from slide_view::begin (function) |