doc/examples/at__object_t_key_type_const.cpp

#include <json.hpp>

using json = nlohmann::json;

int main()
{
    // create JSON object
    json object =
    {
        {"the good", "il buono"},
        {"the bad", "il cativo"},
        {"the ugly", "il brutto"}
    };

    // output element with key "the ugly"
    std::cout << object.at("the ugly") << '\n';

    // try to read from a nonexisting key
    try
    {
        std::cout << object.at("the fast") << '\n';
    }
    catch (std::out_of_range)
    {
        std::cout << "out of range" << '\n';
    }
}