json/docs/examples/operator_array__json_pointer.cpp
Florian Albrechtskirchinger 9aafcbe965
Move UDLs out of the global namespace (#3605)
* Move UDLs into nlohmann::literals::json_literals namespace

* Add 'using namespace' to unit tests

* Add 'using namespace' to examples

* Add 'using namespace' to README

* Move UDL mkdocs pages out of basic_json/

* Update documentation

* Update docset index

* Add JSON_GlobalUDLs CMake option

* Add unit test

* Build examples without global UDLs

* Add CI target
2022-07-31 17:38:52 +02:00

50 lines
1.3 KiB
C++

#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using namespace nlohmann::literals;
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["/number"_json_pointer] << '\n';
// output element with JSON pointer "/string"
std::cout << j["/string"_json_pointer] << '\n';
// output element with JSON pointer "/array"
std::cout << j["/array"_json_pointer] << '\n';
// output element with JSON pointer "/array/1"
std::cout << j["/array/1"_json_pointer] << '\n';
// writing access
// change the string
j["/string"_json_pointer] = "bar";
// output the changed string
std::cout << j["string"] << '\n';
// "change" a nonexisting object entry
j["/boolean"_json_pointer] = true;
// output the changed object
std::cout << j << '\n';
// change an array element
j["/array/1"_json_pointer] = 21;
// "change" an array element with nonexisting index
j["/array/4"_json_pointer] = 44;
// output the changed array
std::cout << j["array"] << '\n';
// "change" the array element past the end
j["/array/-"_json_pointer] = 55;
// output the changed array
std::cout << j["array"] << '\n';
}