#include using json = nlohmann::json; int main() { // create JSON values json j_null; json j_boolean = true; json j_number_integer = 17; json j_number_float = 23.42; json j_object = {{"one", 1}, {"two", 2}}; json j_object_empty(json::value_t::object); json j_array = {1, 2, 4, 8, 16}; json j_array_empty(json::value_t::array); json j_string = "Hello, world"; // call empty() std::cout << std::boolalpha; std::cout << j_null.empty() << '\n'; std::cout << j_boolean.empty() << '\n'; std::cout << j_number_integer.empty() << '\n'; std::cout << j_number_float.empty() << '\n'; std::cout << j_object.empty() << '\n'; std::cout << j_object_empty.empty() << '\n'; std::cout << j_array.empty() << '\n'; std::cout << j_array_empty.empty() << '\n'; std::cout << j_string.empty() << '\n'; }