std::make_tuple
Defined in header <tuple> | ? | ? |
|---|---|---|
template< class... Types > tuple<VTypes...> make_tuple( Types&&... args ); | ? | (since C++11) (until C++14) |
template< class... Types > constexpr tuple<VTypes...> make_tuple( Types&&... args ); | ? | (since C++14) |
创建元组对象，从参数类型推断目标类型。
每人Ti在Types...，对应类型Vi在Vtypes...是std::decay<Ti>::type除非...的适用std::decay结果std::reference_wrapper<X>为某种类型X，在这种情况下，推导的类型是X&...
参数
args | - | zero or more arguments to construct the tuple from |
|---|
返回值
阿std::tuple对象中包含给定值的std::tuple<VTypes...>(std::forward<Types>(t)...).
可能的实施
模板<class T>结构展开[医]使用type=T；}；模板<class T>结构展开[医]REWILE<std：：引用[医]包装器<T>>{使用type=T}；模板<class T>使用特殊[医]衰变[医]t=type Name展开[医]重构包装<type Name std：：衰变<T>*类型>：：类型；模板<class...。类型>自动制造[医]元组%28类型&...args%29{返回std：：tuple<Specible[医]衰变[医]T型<Types>...%28%d：：前进<Types>%28 args%29...%29；}
*。
例
二次
#include <iostream>
#include <tuple>
#include <functional>
std::tuple<int, int> f() // this function returns multiple values
{
int x = 5;
return std::make_tuple(x, 7); // return {x,7}; in C++17
}
int main()
{
// heterogeneous tuple construction
int n = 1;
auto t = std::make_tuple(10, "Test", 3.14, std::ref(n), n);
n = 7;
std::cout << "The value of t is " << "("
<< std::get<0>(t) << ", " << std::get<1>(t) << ", "
<< std::get<2>(t) << ", " << std::get<3>(t) << ", "
<< std::get<4>(t) << ")\n";
// function returning multiple values
int a, b;
std::tie(a, b) = f();
std::cout << a << " " << b << "\n";
}二次
产出：
二次
The value of t is (10, Test, 3.14, 7, 1)
5 7二次
另见
tie | creates a tuple of lvalue references or unpacks a tuple into individual objects (function template) |
|---|---|
forward_as_tuple | creates a tuple of rvalue references (function template) |
tuple_cat | creates a tuple by concatenating any number of tuples (function template) |
apply (C++17) | calls a function with a tuple of arguments (function template) |
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