A GUI toolkit is a set of header files and libraries that makes GUI development easier for developers. There are several GUI toolkits available in the market, few of them are stated as follows:
Microsoft Foundation Class (MFC): It is a set of classes that acts as a wrapper to Win32 api. This comes bundled with commercial versions of Visual Studio. MFC is proprietary and requires a Visual Studio license in order to use it. MFC app have native look and feel.
Qt (pronounced as "cute"): It is a Open source and cross-platform GUI toolkit developed by Digia. Qt is licensed under both commercial and GPL/LGPL license. It is available on wide range of platforms including Windows, Linux, Mac, and so on. Qt drawn GUI is a custom drawn UI and may differ from a standard app on a platform.
wxWidgets: It is another open source and cross-platform GUI toolkit licensed under wxWindows license (based on LGPL but less restrictive). It's generated UI has native look and feel as it uses...