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 values:
std::mdspan mds{vec.data(), vec.size() / 3, 3};
print2D(mds);
// add more elements:
// - reallocation invalidates the mdspan
vec.push_back(42);
// do NOT use the mdspan here without reinitialization
// reinitialize mdspan for new number of elements:
mds = std::mdspan{vec.data(), vec.size() / 3, 3};
print2D(mds);
}