make_pair std::make_pair Defined in header<utility> template<classT1,classT2> std::pair<T1, T2>make_pair(T1 x, T2 y); (until C++11) template<classT1,classT2> std::pair</*V1*/,/*V2*/>make_pair(T1&&x, T2&&y); (si
constexprstd::pair<V1,V2>make_pair(T1&&t, T2&&u); (C++14 起) 构造std::pair对象,从参数类型推导目标类型。 推导结果类型V1与V2是std::decay<T1>::type与std::decay<T2>::type(应用到按值传递的函数参数的通常类型变换),除非应用std::decay到某类型X产生std::reference_wrapper<X>,此情况下推导...
std::tuple_size<std::pair> (C++11) obtains the size of apair (class template specialization) std::tuple_element<std::pair> (C++11) obtains the type of the elements ofpair (class template specialization) std::basic_common_reference<std::pair> ...
constexpr std::pair<V1,V2> make_pair( T1&& t, T2&& u ); (C++14 起) 构造std::pair 对象,从参数类型推导目标类型。 推导结果类型 V1 与V2 是std::decay<T1>::type 与std::decay<T2>::type (应用到按值传递的函数参数的通常类型变换),除非应用 std::decay 到某类型 X 产生std::referenc...
(std::pair<T, U> const& pair) -> typename std::tuple_element<N, std::pair<T, U>>::type { return detail::get_val_dispatch(pair, detail::index_tag<N>{}); } int main() { auto var = std::make_pair(1, std::string{"one"}); std::cout << get_val<0>(var) << " = ...
(add,std::pair(1,2))<<'\n';// Error: can't deduce the function type// std::cout << std::apply(add_generic, std::make_pair(2.0f, 3.0f)) << '\n';// OKstd::cout<<std::apply(add_lambda,std::pair(2.0f,3.0f))<<'\n';// advanced examplestd::tuplemyTuple{25,"Hello"...
问使用std::make_pair与std::string (非rvalue引用问题)EN#include <string>#include <locale>#...
最后这种做法中的 pair<bool, Out> 这个数据结构实现的功能就跟本文要介绍 std::optional 很相似了。 std::optional Fromcppreference -std::optional The class templatestd::optionalmanages anoptionalcontained value, i.e. a value that may or may not be present. ...
We can have a vector of std::reference_wrapper, have it as a member of a class, and more as we see in the next section. 3. Common Use Cases 3.1. With make_pair and make_tuple std::reference_wrapper can be used as an argument to a template function (or constructor) to avoid sp...
auto t = std::make_tuple(1,2,3); // 等效内存模型 class Tuple_eq { public: Tuple_eq() = default; // ... private: int val_3_{3}; int val_2_{2}; int val_1_{1}; }; 这样,我们就理解了 std::tuple 的设计目标以及它的具体设计。 EBCO失效解决办法 最后,我们再来回顾【编译器优...