mdd/thirdparty/json/doc/examples/basic_json__nullptr_t.cpp

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

using json = nlohmann::json;

int main()
{
    // implicitly create a JSON null value
    json j1;

    // explicitly create a JSON null value
    json j2(nullptr);

    // serialize the JSON null value
    std::cout << j1 << '\n' << j2 << '\n';
}