std::remove_extent
From cppreference.com
| 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.
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
|
Helper types
template< class T >
using remove_extent_t = typename remove_extent<T>::type;
|
(since C++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