json/docs/examples/from_json__non_default_constructible.cpp
Niels Lohmann 7b6cf5918b
Documentation change (#3672)
Co-authored-by: Florian Albrechtskirchinger <falbrechtskirchinger@gmail.com>
2022-08-05 19:51:39 +02:00

54 lines
1.1 KiB
C++

#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
namespace ns
{
// a simple struct to model a person (not default constructible)
struct person
{
person(std::string n, std::string a, int aa)
: name(std::move(n)), address(std::move(a)), age(aa)
{}
std::string name;
std::string address;
int age;
};
} // namespace ns
namespace nlohmann
{
template <>
struct adl_serializer<ns::person>
{
static ns::person from_json(const json& j)
{
return {j.at("name"), j.at("address"), j.at("age")};
}
// Here's the catch! You must provide a to_json method! Otherwise, you
// will not be able to convert person to json, since you fully
// specialized adl_serializer on that type
static void to_json(json& j, ns::person p)
{
j["name"] = p.name;
j["address"] = p.address;
j["age"] = p.age;
}
};
} // namespace nlohmann
int main()
{
json j;
j["name"] = "Ned Flanders";
j["address"] = "744 Evergreen Terrace";
j["age"] = 60;
auto p = j.get<ns::person>();
std::cout << p.name << " (" << p.age << ") lives in " << p.address << std::endl;
}