I'm trying to convert a JSON string to Bson Object.

From Stackoverflow answers, I found that I can use like this,

 
    mongo::BSONObj object = mongo::fromjson("name: 'hi'");
 
But, VS code display that both mongo and BSON as undefined. 
 
This is what I have included

#include <bsoncxx/builder/stream/document.hpp>
#include <bsoncxx/json.hpp>
#include <mongocxx/client.hpp>
#include <mongocxx/stdx.hpp>
#include <mongocxx/uri.hpp>
#include <mongocxx/instance.hpp>

using bsoncxx::builder::stream::close_array;
using bsoncxx::builder::stream::close_document;
using bsoncxx::builder::stream::document;
using bsoncxx::builder::stream::finalize;
using bsoncxx::builder::stream::open_array;
using bsoncxx::builder::stream::open_document;