operator-(ranges::zip_view::sentinel)

 

C++

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自立实现与有宿主实现

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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)

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通用工具库

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范围库 (C++20)

算法库

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文件系统库 (C++17)

正则表达式库 (C++11)

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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::zip_view

成员函数

zip_view::zip_view

zip_view::begin

zip_view::end

zip_view::size

推导指引

迭代器

成员函数

zip_view::iterator::iterator

zip_view::iterator::operator*

zip_view::iterator::operator[]

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

非成员函数

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

operator+(zip_view::iterator) operator-(zip_view::iterator)

iter_move(zip_view::iterator)

iter_swap(zip_view::iterator)

哨位

成员函数

zip_view::sentinel::sentinel

非成员函数

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

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

 

template< bool OtherConst >     requires (std::sized_sentinel_for<                 ranges::sentinel_t</*maybe-const*/<Const, Views>>,                 ranges::iterator_t</*maybe-const*/<OtherConst, Views>>> && ...) friend constexpr     std::common_type_t<ranges::range_difference_t</*maybe-const*/<OtherConst, Views>>...> operator-( const iterator<OtherConst>& x, const sentinel& y );	(1)	(C++23 起)
template< bool OtherConst >     requires (std::sized_sentinel_for<                 ranges::sentinel_t</*maybe-const*/<Const, Views>>,                 ranges::iterator_t</*maybe-const*/<OtherConst, Views>>> && ...) friend constexpr     std::common_type_t<ranges::range_difference_t</*maybe-const*/<OtherConst, Views>>...> operator-( const sentinel& y, const iterator<OtherConst>& x );	(2)	(C++23 起)

计算 x 的底层迭代器元组和 y 的底层哨位元组之间的最小距离。

这些函数对常规的无限定或有限定查找不可见，而只能在 zip_view::sentinel<Const> 为实参的关联类时由实参依赖查找找到。

参数

x	-	iterator
y	-	sentinel

返回值

令 current_ 代表 x 的底层迭代器元组，并令 end_ 代表 y 的底层哨位元组。

令 DIST(x, y, i) 为对于某个整数 i 通过等价于 std::get<i>(x.current_) - std::get<i>(y.end_) 的表达式计算所得的距离。

1) 范围 0 ≤ i < sizeof...(Views) 中的所有 i 中的 DIST(x, y, i) 的最小绝对值

2) -(x - y)

示例

运行此代码

#include <cassert>
#include <deque>
#include <list>
#include <ranges>
#include <vector>
 
int main()
{
    auto x = std::vector{1, 2, 3, 4};
    auto y = std::deque{'a', 'b', 'c'};
    auto z = {1.1, 2.2};
    auto w = std::list{1, 2, 3};
 
    auto p = std::views::zip(x, y, z);
    assert(p.begin() - p.end() == +2);
    assert(p.end() - p.begin() == -2);
 
    [[maybe_unused]]
    auto q = std::views::zip(x, y, w);
 
    // 以下代码会引发编译时错误，因为 std::list::iterator 并不支持计算距离所需的 operator-：
    // auto e = q.begin() - q.end();
}