Very very basic C++ class to represent JSON? [on hold]

I searched a lot but cannot find a very basic C++ class to represent JSON. Like something that can be done within an hour. I have seen this, which has list of many C++ - JSON libraries.

List of many JSON libraries in C++

I'm not looking for something which can handle each and every case. I'm looking for something simple and just complete design(Without implementation is fine) so that I can get an idea of how would I store string, array, int, double, object. Most efficient way. I don't want to use BOOST but C++11 is fine.

Consider this question is being asked for an on-site interview. I just need to design it in an hour and show how would I access and/or insert.