std::ranges::adjacent_transform_view<V,F,N>::size

 

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)

元编程库 (C++11)

诊断库

通用工具库

字符串库

容器库

迭代器库

范围库 (C++20)

算法库

数值库

本地化库

输入/输出库

文件系统库 (C++17)

正则表达式库 (C++11)

并发支持库 (C++11)

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 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    sized_range	common_range view viewable_range	input_range output_range forward_range	bidirectional_range    random_access_range contiguous_range	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 ref_view owning_view as_rvalue_viewviews::as_rvalue (C++23)(C++23)   filter_viewviews::filter transform_viewviews::transform take_viewviews::take take_while_viewviews::take_while concat_viewviews::concat (C++26)(C++26)	drop_viewviews::drop drop_while_viewviews::drop_while join_viewviews::join join_with_viewviews::join_with (C++23)(C++23)   lazy_split_viewviews::lazy_split split_viewviews::split views::counted common_viewviews::common	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::adjacent_transform_view

成员函数

adjacent_transform_view::adjacent_transform_view

adjacent_transform_view::begin

adjacent_transform_view::end

adjacent_transform_view::size

迭代器

成员函数

adjacent_transform_view::iterator::iterator

adjacent_transform_view::iterator::operator*

adjacent_transform_view::iterator::operator[]

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

非成员函数

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

operator+(adjacent_transform_view::iterator) operator-(adjacent_transform_view::iterator)

哨位

成员函数

adjacent_transform_view::sentinel::sentinel

非成员函数

operator==(adjacent_transform_view::iterator,adjacent_transform_view::sentinel)

operator-(adjacent_transform_view::iterator,adjacent_transform_view::sentinel)

 

constexpr auto size() requires ranges::sized_range<InnerView>;		(C++23 起)
constexpr auto size() const requires ranges::sized_range<const InnerView>;		(C++23 起)

返回元素数量。

令 inner_ 为 InnerView（即 ranges::adjacent_view<V,N>）类型的底层对象。

1,2) 等价于 return inner_.size();。

参数

(无)

返回值

元素的数量，如果底层视图 V 小于 N 则可能为 ​0​。

示例

运行此代码

#include <ranges>
 
int main()
{
    constexpr static auto v = {1, 2, 3, 4, 5, 6};
 
    auto f = [](auto...) { return 0; }; // dummy
 
    constexpr int width1 {4};
    constexpr auto view1 = v | std::views::adjacent_transform<width1>(f);
    static_assert(view1.size() == 3);
    static_assert(view1.size() == (v.size() - width1 + 1));
 
    constexpr int width2 {8};
    constexpr auto view2 = v | std::views::adjacent_transform<width2>(f);
    // 窗口过宽，因此 view2 没有元素：
    static_assert(view2.size() == 0);
}

参阅

ranges::size (C++20)	返回等于范围大小的整数 (定制点对象)
ranges::ssize (C++20)	返回等于范围大小的有符号整数 (定制点对象)