std::make_move_iterator

 

C++

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功能特性测试宏 (C++20)

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迭代器库

迭代器概念
indirectly_readable (C++20) indirectly_writable (C++20) weakly_incrementable (C++20) incrementable (C++20) input_or_output_iterator (C++20) sentinel_for (C++20) sized_sentinel_for (C++20)	input_iterator (C++20) output_iterator (C++20) forward_iterator (C++20) bidirectional_iterator (C++20) random_access_iterator (C++20) contiguous_iterator (C++20)
迭代器原语
iterator_traits input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tagcontiguous_iterator_tag (C++20) iterator (C++17 中弃用)	incrementable_traits (C++20) indirectly_readable_traits (C++20) iter_value_titer_difference_titer_reference_titer_rvalue_reference_titer_common_reference_t (C++20)(C++20)(C++20)(C++20)(C++20)
算法概念与工具
间接可调用概念
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)
常用算法要求
indirectly_movable (C++20) indirectly_movable_storable (C++20) indirectly_copyable (C++20) indirectly_copyable_storable (C++20)	indirectly_swappable (C++20) indirectly_comparable (C++20) permutable (C++20) mergeable (C++20) sortable (C++20)
工具
indirect_result_t	projected
迭代器适配器
reverse_iterator move_iterator (C++11) 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) back_insert_iterator front_insert_iterator insert_iterator	make_reverse_iterator (C++14) make_move_iterator (C++11) default_sentinel_tdefault_sentinel (C++20)(C++20) unreachable_sentinel_tunreachable_sentinel (C++20)(C++20) make_const_iterator (C++23) make_const_sentinel (C++23) back_inserter front_inserter inserter
流迭代器
istream_iterator ostream_iterator	istreambuf_iterator ostreambuf_iterator
迭代器定制点
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) endcend (C++11)(C++14) sizessize (C++17)(C++20)	rbegincrbegin (C++14)(C++14) rendcrend (C++14)(C++14) empty (C++17) data (C++17)

 

在标头 <iterator> 定义
template< class Iter > std::move_iterator<Iter> make_move_iterator( Iter i );		(C++11 起) (C++17 前)
template< class Iter > constexpr std::move_iterator<Iter> make_move_iterator( Iter i );		(C++17 起)

make_move_iterator 是对给定迭代器 i 构造类型从参数类型推出的 std::move_iterator 的便利函数模板。

参数

i

-

转换成移动迭代器的输入迭代器

返回值

可用于从通过 i 访问的元素移动的 std::move_iterator 。

可能的实现

template< class Iter > constexpr // C++17 起 std::move_iterator<Iter> make_move_iterator( Iter i ) { return std::move_iterator<Iter>(std::move(i)); }

示例

运行此代码

#include <iostream>
#include <list>
#include <vector>
#include <string>
#include <iterator>
 
int main()
{
    std::list<std::string> s{"one", "two", "three"};
 
    std::vector<std::string> v1(s.begin(), s.end()); // copy
 
    std::vector<std::string> v2(std::make_move_iterator(s.begin()),
                                std::make_move_iterator(s.end())); // move
 
    std::cout << "v1 now holds: ";
    for (auto str : v1)
            std::cout << "\"" << str << "\" ";
    std::cout << "\nv2 now holds: ";
    for (auto str : v2)
            std::cout << "\"" << str << "\" ";
    std::cout << "\noriginal list now holds: ";
    for (auto str : s)
            std::cout << "\"" << str << "\" ";
    std::cout << '\n';
}

可能的输出：

v1 now holds: "one" "two" "three"
v2 now holds: "one" "two" "three"
original list now holds: "" "" ""

缺陷报告

下列更改行为的缺陷报告追溯地应用于以前出版的 C++ 标准。

缺陷报告	应用于	出版时的行为	正确行为
LWG 2061	C++11	make_move_iterator 不将数组参数转换成指针	使之转换

参阅

move_iterator (C++11)	解引用结果为右值引用的迭代器适配器 (类模板)
move (C++11)	获得右值引用 (函数模板)