json/docs/examples/nlohmann_define_type_non_intrusive_macro.cpp

#include <iostream>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

namespace ns
{
struct person
{
    std::string name;
    std::string address;
    int age;
};

NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(person, name, address, age)
} // namespace ns

int main()
{
    ns::person p = {"Ned Flanders", "744 Evergreen Terrace", 60};

    // serialization: person -> json
    json j = p;
    std::cout << "serialization: " << j << std::endl;

    // deserialization: json -> person
    json j2 = R"({"address": "742 Evergreen Terrace", "age": 40, "name": "Homer Simpson"})"_json;
    auto p2 = j2.get<ns::person>();

    // incomplete deserialization:
    json j3 = R"({"address": "742 Evergreen Terrace", "name": "Maggie Simpson"})"_json;
    try
    {
        auto p3 = j3.get<ns::person>();
    }
    catch (json::exception& e)
    {
        std::cout << "deserialization failed: " << e.what() << std::endl;
    }
}