Q:

JSON classes in Qt vs other JSON parsers in C++

I'm developing a server/client application in C++ and im using Qt as my IDE as well as some of its libraries. Performance-wise i was told that one of the best ways to transfer data between a server and client was via JSON. However i would like to know the performance differences between the default classes for parsing JSON in Qt (QJsonArray,QJsonObject.. etc) and other C++ parsers, like JSON++ for example..

A:

If Qt classes are not performant enough, you can look at RapidJson: https://github.com/miloyip/rapidjson
Performance comparision:
http://code.google.com/p/rapidjson/wiki/Performance
Good thing about RapidJson (apart from its speed) is easy installation and usage. From their website: 

rapidjson is a header-only library. That means, the only thing to be done is to copy rapidjson/include/rapidjson and its sub-directories to your project or other include paths.

And example also from their wiki page:
#include "rapidjson/document.h"
#include <cstdio>

int main() {
    const char json[] = "{ \"hello\" : \"world\" }";

    rapidjson::Document d;
    d.Parse<0>(json);

    printf("%s\n", d["hello"].GetString());

    return 0;
}

