std::get(std::tuple)
| (1) | |
template< std::size_t I, class... Types >
typename std::tuple_element<I, tuple<Types...> >::type&
get( tuple<Types...>& t );
| (since C++11)
(until C++14) |
template< std::size_t I, class... Types >
constexpr std::tuple_element_t<I, tuple<Types...> >&
get( tuple<Types...>& t );
| (since C++14) |
| (2) | |
template< std::size_t I, class... Types >
typename std::tuple_element<I, tuple<Types...> >::type&&
get( tuple<Types...>&& t );
| (since C++11)
(until C++14) |
template< std::size_t I, class... Types >
constexpr std::tuple_element_t<I, tuple<Types...> >&&
get( tuple<Types...>&& t );
| (since C++14) |
| (3) | |
template< std::size_t I, class... Types >
typename std::tuple_element<I, tuple<Types...> >::type const&
get( const tuple<Types...>& t );
| (since C++11)
(until C++14) |
template< std::size_t I, class... Types >
constexpr std::tuple_element_t<I, tuple<Types...> >const&
get( const tuple<Types...>& t );
| (since C++14) |
template< std::size_t I, class... Types >
constexpr std::tuple_element_t<I, tuple<Types...> >const&&
get( const tuple<Types...>&& t );
| (4) | (since C++17) |
template< class T, class... Types >
constexpr T& get(tuple<Types...>& t);
| (5) | (since C++14) |
template< class T, class... Types >
constexpr T&& get(tuple<Types...>&& t);
| (6) | (since C++14) |
template< class T, class... Types >
constexpr const T& get(const tuple<Types...>& t);
| (7) | (since C++14) |
template< class T, class... Types >
constexpr const T&& get(const tuple<Types...>&& t);
| (8) | (since C++17) |
1-4) Extracts the Ith element from the tuple. I is an integer value in [0, sizeof...(Types)).
5-8) Extracts the element of the tuple t whose type is T. Fails to compile if the tuple has more than one element of that type.
Parameters
| t | - | tuple whose contents to extract |
Return value
A reference to the selected element of t.
Exceptions
Example
#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";
std::cout << "(" << std::get<int>(t) << ", " << std::get<const char*>(t)
<< ", " << std::get<double>(t) << ")\n";
}Output:
(1, Foo, 3.14)
(1, Foo, 3.14)
See also
| | accesses an element of an array
(function template) |
|
(C++11) | accesses an element of a pair
(function template) |
|
(C++17) | reads the value of the variant given the index or the type (if the type is unique), throws on error
(function template) |