I need to use forms, widgets etc. in my program which already takes care of creating a window and such. So the question is, would it be okay to use Windows lib to add the needed features, such as a form with a few widgets without any errors, memory leaks and such, cuz if I recall corretctly, when creating a window using Windows lib you would need to do some things to clean everything up afterwards, does the same apply to what I want to do (just for forms, widgets)?
What compiler do you want to use? If you are writing pure win32 api program then yes, you have to clean up after yourself otherwise it can cause memory leaks even after your program has closed. If that really concerns you then it might be better if you used something else, such as MFC, CLI/c++ Windows Forms, C#, or even VB.NET. Pure win32 api isn't easy to write and requires a lot of code/testing. The others I memtioned make life a lot easier for GUI programming.
The compiler i use is "Visual c++ Express". I'll take a look at using the things you mentioned, though I dont think C# would work alongside my C++ code, would it? Though I see why it would be a good choice for something like this.