Defined in header <type_traits> | ||
|---|---|---|
template< class T > struct remove_extent; | (since C++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.
The behavior of a program that adds specializations for remove_extent is undefined.
| Name | Definition |
|---|---|
type | the type of the element of T |
template< class T > using remove_extent_t = typename remove_extent<T>::type; | (since C++14) |
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; }; |
#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
|
(C++11) | checks if a type is an array type (class template) |
|
(C++11) | obtains the number of dimensions of an array type (class template) |
|
(C++11) | obtains the size of an array type along a specified dimension (class template) |
|
(C++11) | removes all extents from the given array type (class template) |
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