text: #include <json.hpp>
  #include <unordered_map>
  
  using json = nlohmann::json;
  
  int main()
  {
      // create an object from std::map
      std::map<std::string, int> c_map
      {
          {"one", 1}, {"two", 2}, {"three", 3}
      };
      json j_map(c_map);
  
      // create an object from std::unordered_map
      std::unordered_map<const char*, double> c_umap
      {
          {"one", 1.2}, {"two", 2.3}, {"three", 3.4}
      };
      json j_umap(c_umap);
  
      // create an object from std::multimap
      std::multimap<std::string, bool> c_mmap
      {
          {"one", true}, {"two", true}, {"three", false}, {"three", true}
      };
      json j_mmap(c_mmap); // only one entry for key "three" is used
  
      // create an object from std::unordered_multimap
      std::unordered_multimap<std::string, bool> c_ummap
      {
          {"one", true}, {"two", true}, {"three", false}, {"three", true}
      };
      json j_ummap(c_ummap); // only one entry for key "three" is used
  
      // serialize the JSON objects
      std::cout << j_map << '\n';
      std::cout << j_umap << '\n';
      std::cout << j_mmap << '\n';
      std::cout << j_ummap << '\n';
  }
  