NAME

std::span::operator[] - std::span::operator[]

Synopsis

constexpr reference operator[](size_type idx) const;

Returns a reference to the idx-th 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()).

Parameters

idx - the index of the element to access

Return value

A reference to the idx-th element of the sequence, i.e., data()[idx]

Exceptions

Throws nothing.

Example

// Run this code

#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