As no-one else has replied to this I'll give it a bash although its quite a few years since I did any C++.

You have to understand a major difference between C++ and Java, namely there is no virtual machine for C++, so that means the GUI part depends entirely on the operating system. You will not be able to write a C++ GUI program which runs on, say, both Windows and Unix like you can (in principle) with Java.

If you want details of what's available built-in to the Windows platform, http://msdn.microsoft.com/library/default.asp is the place to start. Take a look at the Platform SDK part of the Windows Development section.

Some compilers such as Microsoft's Visual C++ have their own classes to handle GUI (e.g. MFC - Microsoft Foundation Classes). But if you want to do it on the cheap I doubt you'll be interested in Visual C++.

I'm afraid I can't help you if you want to know about Unix, I've never written a single line of C for Unix. Although, you could do worse than use the GNU C compiler (GCC) which is freely available for Win and Unix and is apparently one the finest compilers available.

hth
Phil