iter_swap(std::counted_iterator)

 

C++

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功能特性测试宏 (C++20)

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符号索引

外部库

 

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::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)

 

template< std::indirectly_swappable<I> I2 > friend constexpr void iter_swap( const counted_iterator& x, const std::counted_iterator<I2>& y ) noexcept(noexcept(ranges::iter_swap(x.base(), y.base())));		(C++20 起)

交换两个底层迭代器所指向的对象。

等价于 ranges::iter_swap(x.base(), y.base());。

如果 x.count > 0 && y.count() > 0 是 false，那么行为未定义。	(C++26 前)
如果 x.count > 0 && y.count() > 0 是 false，那么： 如果实现是硬化实现，那么就会发生契约违背。 如果实现不是硬化实现，那么行为未定义。	(C++26 起)

此函数模板对常规的无限定或有限定查找不可见，而只能在 std::counted_iterator<I> 为实参的关联类时由实参依赖查找找到。

参数

x, y

-

要交换所指向元素的迭代器适配器

复杂度

常数。

示例

运行此代码

#include <iostream>
#include <iterator>
#include <list>
#include <vector>

int main()
{
    std::vector p{1, 2, 3, 4},
                q{5, 6, 7, 8};
    
    std::counted_iterator<std::vector<int>::iterator> ip{p.begin(), 2};
    std::counted_iterator<std::vector<int>::iterator> iq{q.begin(), 3};
    
    std::cout << *ip << ' ' << *iq << '\n';
    iter_swap(ip, iq); // ADL
    std::cout << *ip << ' ' << *iq << '\n';
    
    std::list x{0, 1, 3};
    std::counted_iterator<std::list<int>::iterator> ix{x.begin(), 2};
//  iter_swap(ip, ix); // 错误：不可间接交换
}

输出：

1 5
5 1

参阅

swap	交换两个对象的值 (函数模板)
swap_ranges	交换两个范围的元素 (函数模板)
iter_swap	交换两个迭代器所指向的元素 (函数模板)
iter_swap (C++20)	交换两个可解引用对象所引用的值 (定制点对象)
iter_move (C++20)	将解引用底层迭代器的结果转换为其关联的右值引用类型 (函数)