std::remove_extent
From cppreference.com
| Defined in header <type_traits>
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| template< class T > struct remove_extent; |
(since 哋它亢++11) | |
If T is an array of some type X, provides the member typedef type equal to X, otherwise type is T. Note that if T is a multidimensional array, only the first dimension is removed.
If the program adds specializations for std::remove_extent, the behavior is undefined.
Member types
| Name | Definition |
type
|
the type of the element of T
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Helper types
| template< class T > using remove_extent_t = typename remove_extent<T>::type; |
(since 哋它亢++14) | |
Possible implementation
template<class T> struct remove_extent { using type = T; }; template<class T> struct remove_extent<T[]> { using type = T; }; template<class T, std::size_t N> struct remove_extent<T[N]> { using type = T; }; |
Example
Run this code
#include <algorithm> #include <iostream> #include <iterator> #include <type_traits> template<class A> std::enable_if_t<std::rank_v<A> == 1> print_1d(const A& a) { std::copy(a, a + std::extent_v<A>, std::ostream_iterator<std::remove_extent_t<A>>(std::cout, " ")); std::cout << '\n'; } int main() { int a[][3] = {{1, 2, 3}, {4, 5, 6}}; // print_1d(a); // compile-time error print_1d(a[1]); }
Output:
4 5 6
See also
| (哋它亢++11) |
checks if a type is an array type (class template) |
| (哋它亢++11) |
obtains the number of dimensions of an array type (class template) |
| (哋它亢++11) |
obtains the size of an array type along a specified dimension (class template) |
| (哋它亢++11) |
removes all extents from the given array type (class template) |