std::get(std::tuple)

 

C++

语言

概念

实用工具库

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算法库

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正则表达式库 （C++11）

原子操作库 （C++11）

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实用工具库

类型的支持 (basic types, RTTI, type traits)

动态内存管理

错误处理

程序实用工具

可变参数函数

日期和时间

函数对象

initializer_list （C++11）

bitset

hash （C++11）

关系运算符 Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

双和元组 Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

tuple （C++11）

piecewise_construct_t （C++11）

piecewise_construct （C++11）

掉期，远期和移动 Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

forward （C++11）

move （C++11）

move_if_noexcept （C++11）

declval （C++11）

 

std::tuple

成员函数 Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

tuple::tuple

tuple::operator=

tuple::swap

非成员函数 Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

make_tuple

tie

forward_as_tuple

None

operator= operator!= operator< operator<= operator> operator>=

std::swap

get

Helper类 Original: Helper classes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

tuple_size

tuple_element

uses_allocator

ignore

 

template< std::size_t I, class... Types > typename std::tuple_element<I, tuple<Types...> >::type&     get( tuple<Types...>& t );	(1)	（C++11 起）
template< std::size_t I, class... Types > typename std::tuple_element<I, tuple<Types...> >::type&&     get( tuple<Types...>&& t );	(2)	（C++11 起）
template< std::size_t I, class... Types > typename std::tuple_element<I, tuple<Types...> >::type const&     get( const tuple<Types...>& t );	(3)	（C++11 起）

提取Ithelement元素的元组。 I是一个整数值，[0, sizeof...(Types)).

Original:

Extracts the Ith element element from the tuple. I is an integer value in [0, sizeof...(Types)).

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参数

t

-

元组的内容提取 Original: tuple whose contents to extract The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

返回值

1)

参考Ith元素t.

Original:

Reference to the Ith element of t.

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2)

rvalue引用Ith的t元素，除非该元素是左值引用类型，在这种情况下，左值引用被返回.

Original:

Rvalue reference to the Ith element of t, unless the element is of lvalue reference type, in which case lvalue reference is returned.

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3)

const引用的Ith元素t.

Original:

Const reference to the Ith element of t.

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例外

noexcept specification:  

noexcept

  （C++11 起）

为例

#include <iostream>
#include <string>
#include <tuple>
 
int main()
{
    auto t = std::make_tuple(1, "Foo", 3.14);
    std::cout << "(" << std::get<0>(t) << ", " << std::get<1>(t)
              << ", " << std::get<2>(t) << ")\n";
}

Output:

(1, Foo, 3.14)

另请参阅

std::get(std::array)	accesses an element of an array （函数模板）
std::get(std::pair) （C++11）	访问一个一个pair元素 Original: accesses an element of a pair The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）