std::ranges::join_view<V>::iterator<Const>::operator++,--

 

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::join_view

成员函数

join_view::join_view

join_view::base

join_view::begin

join_view::end

推导指引

迭代器

join_view::iterator::iterator

join_view::iterator::operator* join_view::iterator::operator->

join_view::iterator::operator++ join_view::iterator::operator++(int) join_view::iterator::operator-- join_view::iterator::operator--(int)

join_view::iterator::satisfy

operator==(join_view::iterator)

iter_move(join_view::iterator)

iter_swap(join_view::iterator)

哨位

join_view::sentinel::sentinel

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

 

constexpr /*iterator*/& operator++();	(1)	(C++20 起)
constexpr void operator++( int );	(2)	(C++20 起)
constexpr /*iterator*/ operator++( int )     requires /*ref-is-glvalue*/ && ranges::forward_range<Base> &&              ranges::forward_range<ranges::range_reference_t<Base>>;	(3)	(C++20 起)
constexpr iterator& operator--()     requires /*ref-is-glvalue*/ && ranges::bidirectional_range<Base> &&              ranges::bidirectional_range<ranges::range_reference_t<Base>> &&              ranges::common_range<ranges::range_reference_t<Base>>;	(4)	(C++20 起)
constexpr /*iterator*/ operator--( int )     requires /*ref-is-glvalue*/ && ranges::bidirectional_range<Base> &&              ranges::bidirectional_range<ranges::range_reference_t<Base>> &&              ranges::common_range<ranges::range_reference_t<Base>>;	(5)	(C++20 起)

增加或减少底层迭代器。

令 inner_ 和 outer_ 为底层迭代器，并令 parent_ 为指向父 ranges::join_view 的指针，常量 /*ref-is-glvalue*/ 为 std::is_reference_v<ranges::range_reference_t<Base>>。

1) 令 /*inner-range*/ 为：

• *outer_，若 /*ref-is-glvalue*/ == true；
• 否则为 *parent_->inner_。

等价于：

auto&& inner_rng = /*inner-range*/;
if (++inner_ == ranges::end(inner_rng))
{
    ++outer_;
    satisfy();
}
return *this;

2) 等价于：++*this。

3) 等价于：

auto tmp = *this;
++*this;
return tmp;

4) 等价于：

if (outer_ == ranges::end(parent_->base_))
    inner_ = ranges::end(*--outer_);
while (inner_ == ranges::begin(*outer_))
    inner_ = ranges::end(*--outer_);
--inner_;
return *this;

5) 等价于：

auto tmp = *this;
--*this;
return tmp;

参数

（无）

返回值

1,4) *this

2) （无）

3,5) 发生改变之前的 *this 的副本