iter_move(std::counted_iterator)

 

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indirectly_readable (C++20) indirectly_writable (C++20) weakly_incrementable (C++20) incrementable (C++20) is-integer-like is-signed-integer-like (C++20)(C++20)	sentinel_for (C++20) sized_sentinel_for (C++20) input_iterator (C++20) output_iterator (C++20) input_or_output_iterator (C++20)	forward_iterator (C++20) bidirectional_iterator (C++20) random_access_iterator (C++20) contiguous_iterator (C++20)
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input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag (C++20)	iter_value_titer_difference_titer_reference_titer_const_reference_titer_rvalue_reference_titer_common_reference_t (C++20)(C++20)(C++20)(C++23)(C++20)(C++20)	iterator (在 C++17 中已弃用) iterator_traits incrementable_traits (C++20) indirectly_readable_traits (C++20)
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indirectly_unary_invocableindirectly_regular_unary_invocable (C++20)(C++20)	indirect_unary_predicate (C++20) indirect_binary_predicate (C++20)	indirect_equivalence_relation (C++20) indirect_strict_weak_order (C++20)
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indirect_result_t (C++20)	projected (C++20)	projected_value_t (C++26)
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reverse_iterator make_reverse_iterator (C++14) move_iterator (C++11) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20)	front_insert_iterator back_insert_iterator inserter insert_iterator front_inserter back_inserter move_sentinel (C++20)	common_iterator (C++20) counted_iterator (C++20) basic_const_iterator (C++23) const_iterator (C++23) const_sentinel (C++23) make_const_iterator (C++23) make_const_sentinel (C++23)
流迭代器 istream_iterator    ostream_iterator istreambuf_iterator ostreambuf_iterator	迭代器自定义点 ranges::iter_move (C++20) ranges::iter_swap (C++20)
迭代器操作 advance distance prev (C++11)   next (C++11) ranges::advance (C++20) ranges::distance (C++20) ranges::prev (C++20) ranges::next (C++20)	范围访问 begincbegin (C++11)(C++14) rbegincrbegin (C++14)(C++14)   endcend (C++11)(C++14) rendcrend (C++14)(C++14)   sizessize (C++17)(C++20) empty (C++17) data (C++17)

 

std::counted_iterator

成员函数

counted_iterator::counted_iterator

counted_iterator::operator=

counted_iterator::base

counted_iterator::count

counted_iterator::operator*counted_iterator::operator->

counted_iterator::operator[]

counted_iterator::operator++counted_iterator::operator++(int)counted_iterator::operator+counted_iterator::operator+=counted_iterator::operator--counted_iterator::operator--(int)counted_iterator::operator-counted_iterator::operator-=

非成员函数

operator==operator<=> (C++20)(C++20)

operator==(default_sentinel_t) (C++20)

operator+ (C++20)

operator- (C++20)

operator-(default_sentinel_t) (C++20)

iter_move (C++20)

iter_swap (C++20)

辅助类

iterator_traits<std::counted_iterator> (C++20)

 

friend constexpr decltype(auto) iter_move( const std::counted_iterator& i )     noexcept(noexcept(ranges::iter_move(i.base())))         requires std::input_iterator<I>;		(自 C++20 起)

将解引用底层迭代器的结果强制转换为其关联的右值引用类型。

函数体等效于 return ranges::iter_move(i.base());。

此函数对于普通的非限定查找或限定查找不可见，并且只能通过实参依赖查找在 std::counted_iterator<I> 是实参的关联类时找到。

如果 i.count() 等于 ​0​，则行为未定义。

参数

i

-

源迭代器适配器

返回值

一个右值引用或一个纯右值临时对象。

复杂度

常数。

示例

运行此代码

#include <iomanip>
#include <iostream>
#include <iterator>
#include <string>
#include <vector>
 
void print(auto const& rem, auto const& v)
{
    std::cout << rem << '[' << size(v) << "] {";
    for (char comma[]{0, ' ', 0}; auto const& s : v)
        std::cout << comma << std::quoted(s), *comma = ',';
    std::cout << "}\n";
}
 
int main()
{
    std::vector<std::string> p{"Alpha", "Bravo", "Charlie"}, q;
    print("p", p);
    print("q", q);
 
    using RI = std::counted_iterator<std::vector<std::string>::iterator>;
 
    for (RI iter{p.begin(), 2}; iter != std::default_sentinel; ++iter)
        q.emplace_back(/* ADL */ iter_move(iter));
 
    print("p", p);
    print("q", q);
}

可能的输出

p[3] {"Alpha", "Bravo", "Charlie"}
q[0] {}
p[3] {"", "", "Charlie"}
q[2] {"Alpha", "Bravo"}

缺陷报告

以下行为变更缺陷报告被追溯应用于先前发布的 C++ 标准。

DR	应用于	已发布的行为	正确的行为
LWG 3953	C++20	返回类型为 std::iter_rvalue_reference_t<I>	更改为 decltype(auto)

参见

iter_move (C++20)	将解引用对象的结果强制转换为其关联的右值引用类型 (自定义点对象)
iter_swap (C++20)	交换两个底层迭代器指向的对象 (函数模板)
move (C++11)	将实参转换为 xvalue (函数模板)
move_if_noexcept (C++11)	如果移动构造函数不抛出异常，则将实参转换为 xvalue (函数模板)
forward (C++11)	转发函数实参并使用类型模板实参来保留其值类别 (函数模板)
ranges::move (C++20)	将某个范围的元素移动到新的位置 (算法函数对象)
ranges::move_backward (C++20)	以向后顺序将某个范围的元素移动到新的位置 (算法函数对象)