constexpr reference operator[]( size_type idx ) const; | (since C++20) |
Returns a reference to the idxth element of the sequence. The behavior is undefined if idx is out of range (i.e., if it is greater than or equal to size()).
| idx | - | the index of the element to access |
A reference to the idxth element of the sequence, i.e., data()[idx].
Throws nothing.
#include <cstddef>
#include <iostream>
#include <span>
#include <utility>
void reverse(std::span<int> span)
{
for (std::size_t i = 0, j = std::size(span); i < j; ++i)
{
--j;
std::swap(span[i], span[j]);
}
}
void print(std::span<const int> const span)
{
for (int element : span)
std::cout << element << ' ';
std::cout << '\n';
}
int main()
{
int data[]{1, 2, 3, 4, 5};
print(data);
reverse(data);
print(data);
}Output:
1 2 3 4 5 5 4 3 2 1
|
(C++20) | returns a pointer to the beginning of the sequence of elements (public member function) |
|
(C++20) | returns the number of elements in the sequence (public member function) |
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