#include #include using json = nlohmann::json; using json_editable_document = nlohmann::json_editable_document; using json_editable_view = nlohmann::json_editable_view; int main() { // a configuration file, as it might be read from disk const std::string text = R"({"name": "cache", "host": "db1", "port": 6379, "price": 19.90})"; std::cout << text << "\n\n"; // patch two fields -- "price" is never touched json_editable_document doc = json_editable_document::parse(text); doc.set(doc.root(), "host", "db2"); doc.set(doc.root(), "retries", 3); // member order (the new member at the end) and the untouched number's // exact spelling survive std::cout << doc.root().dump(-1, ' ', false, json_editable_view::number_format::source) << '\n'; // the same patch on a plain json value: keys are sorted (object_t is a // std::map), and "price" is rewritten even though the patch never // touched it json plain = json::parse(text); plain["host"] = "db2"; plain["retries"] = 3; std::cout << plain.dump() << '\n'; }