std::ranges::take_view<V>:: begin

Returns an iterator to the first element of the take_view .

Overload (1) does not participate in overload resolution if V is a simple view (that is, if V and const V are views with the same iterator and sentinel types).

Parameters

(none)

Return value

The result depends on the concepts satisfied by possibly const-qualified underlying view type Base , which is V for ( 1 ) or const V for ( 2 ) .

Let base_ be the underlying view, count_ be the underlying counter (equals to ​ 0 ​ if take_view was default initialized).

Example

#include <concepts>
#include <forward_list>
#include <iostream>
#include <ranges>
#include <string_view>
#include <type_traits>
using namespace std::literals;
 
int main()
{
    {
        static constexpr auto v = {"∀x"sv, "∃y"sv, "ε"sv, "δ"sv};
        auto view = std::ranges::take_view(v, 8);
        auto iter = view.begin();
        std::cout << *iter << '\n';
        static_assert(
            std::ranges::sized_range<decltype(v)> and
            std::ranges::random_access_range<decltype(v)> and
            std::is_same_v<decltype(iter), decltype(std::ranges::begin(v))>
        );
    }
 
    {
        std::forward_list v = {"Ax"sv, "Ey"sv, "p"sv, "q"sv};
        auto view = std::ranges::take_view(v, 8);
        auto iter = view.begin();
        std::cout << *iter << '\n';
        static_assert(
            not std::ranges::sized_range<decltype(v)> and
            not std::ranges::random_access_range<decltype(v)> and
            std::is_same_v<decltype(iter),
                std::counted_iterator<
                    std::forward_list<std::string_view>::iterator>>
        );
    }
}

∀x
Ax

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also