Qt is a cross-platform toolkit for creating applications with a graphical user interface (GUI).
This framework is available under commercial and open-source licences and provides the programmer with many programming tools and pre-made GUI elements that are easy to use. Qt is commonly used not only for desktops but also for mobile application development.
Qt can be installed by directly downloading the package from Qt website. It is also available in the commonly used Linux package repositories. The main development tool provided in the Qt toolkit is called Qt Creator.