Qt has been developed as a cross-platform framework and has been provided free to the public for years. It's mainly used to build GUI applications. It also provides thousands of APIs for easier development.
Qt 5, the latest major version of Qt, has once again proven to be the most popular cross-platform toolkit. With all these platform-independent classes and functions, you only need to code once, and then you can make it run everywhere.
Chapter 1, Creating Your First Qt Application, takes you through the fundamental concepts ...