ranges/asrvaluecp.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 <print>
#include <string>
#include <vector>
#include <ranges>

int main()
{
  std::vector<std::string> coll1{"X", "Y"};
  std::vector<std::string> coll2{"A", "B"};
  std::vector<std::string> coll3{"1", "2"};
  std::println("coll1: {}", coll1);
  std::println("coll2: {}", coll2);
  std::println("coll3: {}", coll3);

  // BAD:
  auto vec = std::views::cartesian_product(coll1 | std::views::as_rvalue,
                                           coll2 | std::views::as_rvalue,
                                           coll3 | std::views::as_rvalue)
               | std::ranges::to<std::vector>();
  std::println("vec:   {}", vec);
}