This is Qt5 tutorial. In this tutorial, you will learn the basics of GUI programming with Qt5 and C++. The Qt5 tutorial is suitable of beginners and intermediate programmers. Note that the tutorial uses features of C++.
Qt is a cross-platform application development framework. Some of the well known applications developed with Qt are KDE, Opera, Google Earth, and Skype. Qt was first publicly released on May 1995. It is dual licensed. That means, it can be used for creating open source applications as well as commercial ones. Qt toolkit is a very powerful toolkit. It is well established in the open source community.