lib/mdspanrev.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 <vector>
#include <mdspan>
#include "print2d.hpp"

int main()
{
  std::vector vec{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};

  // mdspan with rows of 3 reversed values:
  std::mdspan mds{vec.data()+2,
                  std::layout_stride::mapping{std::extents{vec.size()/3, 3},
                                              std::array{3, -1}}};
  print2D(mds);

  // append new elements to the collection:
  vec.insert(vec.end(), {101, 102, 103, 104, 105, 106, 107, 108, 109});

  // reinitialize the mdspan:
  mds = decltype(mds){vec.data()+2,
                      std::layout_stride::mapping{std::extents{vec.size()/3, 3},
                                                  std::array{3, -1}}};
  print2D(mds);
}