std::tuple_element<std::tuple>

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Defined in header `<tuple>`

template< std::size_t I, class T > class tuple_element; /* undefined */	(1)	(C++11 feature)

template< std::size_t I, class... Types > class tuple_element< I, tuple<Types...> >;	(2)	(C++11 feature)

template< std::size_t I, class T > class tuple_element< I, const T > { typedef typename std::add_const<typename std::tuple_element<I, T>::type>::type type; };	(3)	(C++11 feature)

template< std::size_t I, class T > class tuple_element< I, volatile T > { typedef typename std::add_volatile<typename std::tuple_element<I, T>::type>::type type; };	(4)	(C++11 feature)

template< size_t I, class T > class tuple_element< I, const volatile T > { typedef typename std::add_cv<typename std::tuple_element<I, T>::type>::type type; };	(5)	(C++11 feature)

Provides compile-type indexed access to the types of the elements of the tuple.

[edit] Member types


Member type	Definition

type	the type of Ith element of the tuple, where I is in `[0, sizeof...(Types))`

[edit] Equivalent definition

template< std::size_t I, class T >
struct tuple_element;
 
// recursive case
template<std::size_t I, class Head, class... Tail >
struct tuple_element<I, std::tuple<Head, Tail...>>
    : std::tuple_element<I-1, std::tuple<Tail...>> { };
 
// base case
template< class Head, class... Tail >
struct tuple_element<0, std::tuple<Head, Tail...>> {
   typedef Head type;
};

std::tuple_element<std::tuple>

From Cppreference

[edit] Member types

[edit] Equivalent definition

[edit] Example