std::ranges::cartesian_product_view<First, Vs...>::begin

 

C++

编译器支持

自立实现与有宿主实现

语言

标准库

标准库标头

具名要求

功能特性测试宏 (C++20)

语言支持库

概念库 (C++20)

诊断库

内存管理库

元编程库 (C++11)

通用工具库

容器库

迭代器库

范围库 (C++20)

算法库

字符串库

文本处理库

数值库

日期和时间库

输入/输出库

文件系统库 (C++17)

并发支持库 (C++11)

执行控制库 (C++26)

技术规范

符号索引

外部库

 

范围库

范围访问 begin cbegin   end cend rbegin crbegin   rend crend size ssize   data cdata reserve_hint (C++26)   empty

范围转换 std::from_range_t std::from_range (C++23)(C++23)     to (C++23)

悬垂迭代器处理 dangling borrowed_iterator_t borrowed_subrange_t

范围原语
range_size_trange_difference_trange_value_t elements_of (C++23)	iterator_tconst_iterator_tsentinel_tconst_sentinel_t (C++23)(C++23)	range_reference_trange_const_reference_trange_rvalue_reference_trange_common_reference_t (C++23)

范围概念
range borrowed_range    common_range	sized_range viewable_range    view	input_range output_range forward_range	bidirectional_range    random_access_range contiguous_range	approximately_sized_range (C++26) constant_range (C++23)

视图
view_interface	subrange

范围工厂
empty_viewviews::empty	single_viewviews::single	basic_istream_viewviews::istream	iota_viewviews::iota	repeat_viewviews::repeat (C++23)(C++23)

范围适配器
views::all_tviews::all as_rvalue_viewviews::as_rvalue (C++23)(C++23)   filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while common_viewviews::common views::counted to_input_viewviews::to_input (C++26)(C++26)	ref_view drop_viewviews::drop drop_while_viewviews::drop_while lazy_split_viewviews::lazy_split split_viewviews::split join_viewviews::join join_with_viewviews::join_with (C++23)(C++23)   concat_viewviews::concat (C++26)(C++26) cache_latest_viewviews::cache_latest (C++26)(C++26)	owning_view reverse_viewviews::reverse as_const_viewviews::as_const (C++23)(C++23) elements_viewviews::elements keys_viewviews::keys values_viewviews::values enumerate_viewviews::enumerate (C++23)(C++23) zip_viewviews::zip (C++23)(C++23) zip_transform_viewviews::zip_transform (C++23)(C++23)	adjacent_viewviews::adjacent (C++23)(C++23) views::pairwise (C++23) adjacent_transform_viewviews::adjacent_transform (C++23)(C++23) views::pairwise_transform (C++23) chunk_viewviews::chunk (C++23)(C++23) slide_viewviews::slide (C++23)(C++23) chunk_by_viewviews::chunk_by (C++23)(C++23) stride_viewviews::stride (C++23)(C++23) cartesian_product_viewviews::cartesian_product (C++23)(C++23)

范围生成器 std::generator (C++23)

范围适配器闭包对象 range_adaptor_closure (C++23)

范围适配器对象

辅助项
copyable-box movable-box (C++23 前)  (C++23)	simple-view non-propagating-cache

 

std::ranges::cartesian_product_view

成员函数

cartesian_product_view::cartesian_product_view

cartesian_product_view::begin

cartesian_product_view::end

cartesian_product_view::size

推导指引

迭代器

成员函数

cartesian_product_view::iterator::iterator

cartesian_product_view::iterator::operator*

cartesian_product_view::iterator::operator[]

cartesian_product_view::iterator::operator++ cartesian_product_view::iterator::operator++(int) cartesian_product_view::iterator::operator-- cartesian_product_view::iterator::operator--(int) cartesian_product_view::iterator::operator+= cartesian_product_view::iterator::operator-=

cartesian_product_view::iterator::next

cartesian_product_view::iterator::prev

cartesian_product_view::iterator::distance_from

非成员函数

operator==(cartesian_product_view::iterator) operator<=>(cartesian_product_view::iterator)

operator+(cartesian_product_view::iterator) operator-(cartesian_product_view::iterator)

iter_move(cartesian_product_view::iterator)

iter_swap(cartesian_product_view::iterator)

 

constexpr iterator<false> begin() requires (!/*simple-view*/<First> || ... || !/*simple-view*/<Vs>);	(1)	(C++23 起)
constexpr iterator<true> begin() const requires (ranges::range<const First> && ... && ranges::range<const Vs>);	(2)	(C++23 起)

返回指向 cartesian_product_view 首元素的迭代器。

令 bases_ 为各底层视图的元组。

1) 等价于 return /*iterator*/<false>(tuple-transform(ranges::begin, bases_));。

2) 等价于 return /*iterator*/<true>(tuple-transform(ranges::begin, bases_));。

参数

（无）

返回值

指向首元素的迭代器。

示例

运行此代码

#include <array>
#include <format>
#include <iostream>
#include <ranges>
#include <string_view>
#include <tuple>
using namespace std::literals;

int main()
{
    constexpr auto a = std::array{"Curiously"sv, "Recurring"sv, "Template"sv, "Pattern"sv};

    constexpr auto v = std::ranges::cartesian_product_view(a[0], a[1], a[2], a[3]);

    constexpr std::tuple<char const&,
                         char const&,
                         char const&,
                         char const&> first{*v.begin()};

    std::cout << std::format("{}{}{}{}{}",
                             std::get<0>(first),
                             std::get<1>(first),
                             std::get<2>(first),
                             std::get<3>(first),
                             '\n');
}

输出：

CRTP

参阅

end	返回 指向末尾的迭代器或哨位 (公开成员函数)
ranges::begin (C++20)	返回指向范围起始的迭代器 (定制点对象)