mdspan/mdspanstride2.cpp

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 <iostream>
#include <vector>
#include <ranges>
#include <mdspan>
#include "print3d.hpp"

int main()
{
  std::vector vec{std::from_range, std::views::iota(1, 101)};  // elements from 1 to 100

  // 2 blocks with offset 2 of 5 rows with offset 12 of 3 columns with offset 4:
  std::mdspan mds{vec.data(),
                  std::layout_stride::mapping{std::extents{2, 5, 3},
                                              std::array{2, 12, 4}}};

  // double check that the size fits:
  if (mds.mapping().required_span_size() > vec.size()) {
    std::cerr << "ERROR: underlying data has not enough elements\n";
    return 1;
  }

  print3D(mds);
}