std::array<T,N>::data
T* data() noexcept; |
(since C++11) (until C++17) |
|
constexpr T* data() noexcept; |
(since C++17) | |
const T* data() const noexcept; |
(since C++11) (until C++17) |
|
constexpr const T* data() const noexcept; |
(since C++17) |
Returns pointer to the underlying array serving as element storage. The pointer is such that range [data(); data() + size()) is always a valid range, even if the container is empty (data() is not dereferenceable in that case).
Parameters
(none).
Return value
Pointer to the underlying element storage. For non-empty containers, the returned pointer compares equal to the address of the first element.
Complexity
Constant.
Notes
If size() is 0, data() may or may not return a null pointer.
Example
#include <cstddef>
#include <iostream>
#include <span>
#include <array>
void pointer_func(const int* p, std::size_t size)
{
std::cout << "data = ";
for (std::size_t i = 0; i < size; ++i)
std::cout << p[i] << ' ';
std::cout << '\n';
}
void span_func(std::span<const int> data) // since C++20
{
std::cout << "data = ";
for (const int e : data)
std::cout << e << ' ';
std::cout << '\n';
}
int main()
{
std::array<int,4> container { 1, 2, 3, 4 };
// Prefer container.data() over &container[0]
pointer_func(container.data(), container.size());
// std::span (C++20) is a safer alternative to separated pointer/size.
span_func({container.data(), container.size()});
}
Output:
data = 1 2 3 4 data = 1 2 3 4
See also
|
(C++11)
|
access the first element (public member function) |
|
(C++11)
|
access the last element (public member function) |
|
(C++11)
|
returns the number of elements (public member function) |
|
(C++20)
|
a non-owning view over a contiguous sequence of objects (class template) |
|
(C++17)
|
obtains the pointer to the underlying array (function template) |
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