C++ and Qt

Hi. I've been looking at Qt to create GUIs and it looks useful.

However I have tens of thousands of lines of C++ that I want to maintain. Can I integrate my C++ classes and code within Qt applications?

I note Qt offers file handling for example as a substitute for fstreams. Presumably you cannot use fstreams within say a button slot to read a parameter file?

Any help much appreciated. Cheers

Sorry folks (although hopefully it might help someone).

I had an environment issue but now I have embedded an 'ifstream' into an event (a QtSlot).

So I'm guessing I can fully integrate my cherished C++ code within the GUI QT stuff.

Enjoy