json/doc/examples/at_json_pointer.cpp
2017-03-08 23:30:38 +01:00

45 lines
1.1 KiB
C++

#include <json.hpp>
using json = nlohmann::json;
int main()
{
// create a JSON value
json j =
{
{"number", 1}, {"string", "foo"}, {"array", {1, 2}}
};
// read-only access
// output element with JSON pointer "/number"
std::cout << j.at("/number"_json_pointer) << '\n';
// output element with JSON pointer "/string"
std::cout << j.at("/string"_json_pointer) << '\n';
// output element with JSON pointer "/array"
std::cout << j.at("/array"_json_pointer) << '\n';
// output element with JSON pointer "/array/1"
std::cout << j.at("/array/1"_json_pointer) << '\n';
// writing access
// change the string
j.at("/string"_json_pointer) = "bar";
// output the changed string
std::cout << j["string"] << '\n';
// change an array element
j.at("/array/1"_json_pointer) = 21;
// output the changed array
std::cout << j["array"] << '\n';
// try to use an invalid JSON pointer
try
{
auto ref = j.at("/number/foo"_json_pointer);
}
catch (json::out_of_range& e)
{
std::cout << e.what() << '\n';
}
}