The following code example is taken from the book
C++23 - The Complete Guide
by Nicolai M. Josuttis,
Leanpub, 2026
The code is licensed under a
Creative Commons Attribution 4.0 International License.
// raw code
#include <print>
#include <vector>
#include <ranges>
#include <mdspan>
#include "print3d.hpp"
int main()
{
std::vector vec{std::from_range, std::views::iota(1, 81)}; // vector with 1 to 80
// mdspan of 2 * 5 * 3 elements with column-major order layout:
std::mdspan<int, std::dextents<std::size_t, 3>, std::layout_left>
mdsL{vec.data(), 2, 5, 3};
print3D(mdsL);
// define the mapping:
std::layout_left::mapping mapL3D{std::extents{2, 5, 3}};
std::println("required_span_size(): {}", mapL3D.required_span_size());
// and initialize an mdspan with it:
std::mdspan mds2{vec.data(), mapL3D};
static_assert(std::same_as<decltype(mdsL), decltype(mds2)>);
std::println("size: {}", mdsL.size());
std::println("same mapping: {}", mdsL.mapping() == mapL3D);
}