#include using json = nlohmann::json; int main() { // create two JSON objects json j1 = {{"one", "eins"}, {"two", "zwei"}}; json j2 = {{"eleven", "elf"}, {"seventeen", "siebzehn"}}; // output objects std::cout << j1 << '\n'; std::cout << j2 << '\n'; // insert range from j2 to j1 j1.insert(j2.begin(), j2.end()); // output result of insert call std::cout << j1 << '\n'; }