1 #include <iostream> 2 #include <nlohmann/json.hpp> 3 4 using json = nlohmann::json; 5 using namespace nlohmann::literals; 6 main()7int main() 8 { 9 // create a JSON value 10 json j = 11 { 12 {"number", 1}, {"string", "foo"}, {"array", {1, 2}} 13 }; 14 15 std::cout << std::boolalpha 16 << j.contains("/number"_json_pointer) << '\n' 17 << j.contains("/string"_json_pointer) << '\n' 18 << j.contains("/array"_json_pointer) << '\n' 19 << j.contains("/array/1"_json_pointer) << '\n' 20 << j.contains("/array/-"_json_pointer) << '\n' 21 << j.contains("/array/4"_json_pointer) << '\n' 22 << j.contains("/baz"_json_pointer) << std::endl; 23 24 try 25 { 26 // try to use an array index with leading '0' 27 j.contains("/array/01"_json_pointer); 28 } 29 catch (json::parse_error& e) 30 { 31 std::cout << e.what() << '\n'; 32 } 33 34 try 35 { 36 // try to use an array index that is not a number 37 j.contains("/array/one"_json_pointer); 38 } 39 catch (json::parse_error& e) 40 { 41 std::cout << e.what() << '\n'; 42 } 43 } 44