Qt - Cross-Platform C++ Development
Qt sets the standard for high-performance, cross-platform application development. It includes a C++ class library and tools for cross-platform development and internationalization.
The Qt Class Libraries implement the more than 400 GUI and non-GUI classes that make up the Qt API. These classes fills in the missing pieces in the C++ standard libraries, and ensure that programmers can spend more of their time creating value-adding application logic and less on housekeeping tasks.