how to read and parse a json file with rapidjson
FILE *fp = fopen("input.json", "r"); // stupid windows need rb
char buf[0XFFFF];
//FileReadStream(FILE *fp, char *buffer, std::size_t bufferSize)
rapidjson::FileReadStream input(fp, buf, sizeof(buf));
rapidjson::Document document;
document.ParseStream(input);
fclose(fp);
cout << document["hello"].GetString() << endl;