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

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< cpp‎ | ranges‎ | slide view
C++
Ranges library
Range adaptors
std::ranges::slide_view
Member functions
slide_view::begin
Deduction guides
Iterator
Member functions
Non-member functions
Sentinel
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_) ;

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

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

See also

 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)
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