std::make_pair
Defined in header <utility> | | |
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template< class T1, class T2 > std::pair<T1,T2> make_pair( T1 t, T2 u ); | | (until C++11) |
template< class T1, class T2 > std::pair<V1,V2> make_pair( T1&& t, T2&& u ); | | (since C++11) (until C++14) |
template< class T1, class T2 > constexpr std::pair<V1,V2> make_pair( T1&& t, T2&& u ); | | (since C++14) |
创建std::pair对象，从参数类型推断目标类型。
The deduced types V1 and V2 are std::decay<T1>::type and std::decay<T2>::type (the usual type transformations applied to arguments of functions passed by value) unless application of std::decay results in std::reference_wrapper<X> for some type X, in which case the deduced type is X&. | (since C++11) |
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参数
t, u | - | the values to construct the pair from |
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返回值
安std::pair对象，其中包含给定的值。
例
二次
#include <iostream>
#include <utility>
#include <functional>
int main()
{
int n = 1;
int a[5] = {1, 2, 3, 4, 5};
// build a pair from two ints
auto p1 = std::make_pair(n, a[1]);
std::cout << "The value of p1 is "
<< "(" << p1.first << ", " << p1.second << ")\n";
// build a pair from a reference to int and an array (decayed to pointer)
auto p2 = std::make_pair(std::ref(n), a);
n = 7;
std::cout << "The value of p2 is "
<< "(" << p2.first << ", " << *(p2.second + 2) << ")\n";
}二次
产出：
二次
The value of p1 is (1, 2)
The value of p2 is (7, 3)二次
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