std::swap(std::tuple)

 

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std::tuple

成员函数

tuple::tuple

tuple::operator=

tuple::swap

非成员函数

make_tuple

tie

forward_as_tuple

tuple_cat

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

swap(std::tuple)

get(std::tuple)

辅助概念

tuple-like (C++23)

辅助类

tuple_size<std::tuple>

tuple_element<std::tuple>

uses_allocator<std::tuple>

basic_common_reference<std::tuple> (C++23)

common_type<std::tuple> (C++23)

formatter<std::tuple> (C++23)

ignore

推导指南(C++17)

 

定义在头文件 <tuple> 中
	(1)
template< class... Types > void swap( std::tuple<Types...>& lhs,            std::tuple<Types...>& rhs ) noexcept(/* see below */);			(自 C++11 起) (直到 C++20)
template< class... Types > constexpr void swap( std::tuple<Types...>& lhs,                      std::tuple<Types...>& rhs ) noexcept(/* see below */);			(自 C++20 起)
template< class... Types > constexpr void swap( const std::tuple<Types...>& lhs,                      const std::tuple<Types...>& rhs ) noexcept(/* see below */);		(2)	(自 C++23 起)

交换 lhs 和 rhs 的内容。等效于 lhs.swap(rhs).

1) 此重载仅在对所有 i 从 0 到 sizeof...(Types)，std::is_swappable_v<Ti> 为 true 时参与重载解析。 2) 此重载仅在对所有 i 从 0 到 sizeof...(Types)，std::is_swappable_v<const Ti> 为 true 时参与重载解析。

(自 C++17 起)

参数

lhs, rhs

-

要交换其内容的元组

返回值

(无)

异常

noexcept 规范：  

noexcept(noexcept(lhs.swap(rhs)))

示例

运行此代码

#include <iostream>
#include <string>
#include <tuple>
 
int main()
{
    std::tuple<int, std::string, float> p1{42, "ABCD", 2.71}, p2;
    p2 = std::make_tuple(10, "1234", 3.14);
 
    auto print_p1_p2 = [&](auto rem)
    {
        std::cout << rem
                  << "p1 = {" << std::get<0>(p1)
                  << ", "     << std::get<1>(p1)
                  << ", "     << std::get<2>(p1) << "}, "
                  << "p2 = {" << std::get<0>(p2)
                  << ", "     << std::get<1>(p2)
                  << ", "     << std::get<2>(p2) << "}\n";
    };
 
    print_p1_p2("Before p1.swap(p2): ");
    p1.swap(p2);
    print_p1_p2("After  p1.swap(p2): ");
    swap(p1, p2);
    print_p1_p2("After swap(p1, p2): ");
}

输出

Before p1.swap(p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14}
After  p1.swap(p2): p1 = {10, 1234, 3.14}, p2 = {42, ABCD, 2.71}
After swap(p1, p2): p1 = {42, ABCD, 2.71}, p2 = {10, 1234, 3.14}

另请参阅

swap	交换两个 tuple 的内容 (公共成员函数)
std::swap(std::pair) (C++11)	专门化了 std::swap 算法 (函数模板)