std::move_iterator<Iter>::operator*,->

 

C++

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符号索引

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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) 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)
迭代器原语
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 (C++17 弃用) iterator_traits incrementable_traits (C++20) indirectly_readable_traits (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 (C++20)	projected (C++20)	projected_value_t (C++26)
迭代器适配器
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) 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::move_iterator

成员函数

move_iterator::move_iterator

move_iterator::operator=

move_iterator::base

move_iterator::operator*move_iterator::operator->

move_iterator::operator[]

move_iterator::operator++move_iterator::operator+move_iterator::operator+=move_iterator::operator--move_iterator::operator-move_iterator::operator-=

非成员函数

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

operator==(move_sentinel) (C++20)

operator+

operator-

operator-(move_sentinel) (C++20)

iter_move (C++20)

iter_swap (C++20)

make_move_iterator (C++11)

 

reference operator*()const;	(1)	(C++11 起) (C++17 起为 constexpr)
pointer operator->()const;	(2)	(C++11 起) (C++17 起为 constexpr) (C++20 弃用)

返回到当前元素的右值引用或指针。

返回值

1)static_cast<reference>(*current )(C++20 前)ranges::iter_move(current )(C++20 起)

2)current

注解

operator-> 被弃用的原因是在解引用它的结果时可能会产生左值。这可能导致意外行为。

示例

运行此代码

#include <iomanip>#include <iostream>#include <iterator>#include <string>#include <vector>   void print(auto rem, constauto& v){for(std::cout<< rem;constauto& e : v)std::cout<<std::quoted(e)<<' ';std::cout<<'\n';}   int main(){std::vector<std::string> p{"alpha", "beta", "gamma", "delta"}, q; print("1) p: ", p);for(std::move_iterator it{p.begin()}, end{p.end()}; it != end;++it){ it->push_back('!');// 调用 -> string::push_back(char) q.emplace_back(*it);// *it <- 重载 (1)} print("2) p: ", p); print("3) q: ", q);   std::vector v{1, 2, 3};std::move_iterator it{v.begin()};// *it = 13; // 错误：将右值用作左值}

可能的输出：

1) p: "alpha" "beta" "gamma" "delta" 2) p: "" "" "" "" 3) q: "alpha!" "beta!" "gamma!" "delta!"

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 2106	C++11	*current 产生纯右值的情况下 operator* 会返回悬垂引用	此时直接返回该对象

参阅

operator[]

按索引访问元素 (公开成员函数)