How to Integrate Qt with 'C'

[jacek]

I will be much grateful if anybody can give me a simple example where some code written in C [some simple application, like a hello world ] is executed through Qt [ie., through a Qt UI ].

Do you want to execute a C appplication from within Qt application or simply call some C functions from Qt code?

You can do the latter without any problems, since C++ is compatible with C. All you need is to wrap C headers in extern "C" block. For the former use QProcess.