The QLCDNumber widget displays a number with LCD-like digits.| doc.qt.io
The QFrame class is the base class of widgets that can have a frame.| doc.qt.io
An overview of Qt's signals and slots inter-object communication mechanism. Signals and slots are used for communication between objects. The signals and slots mechanism is a central feature of Qt and probably the part that differs most from the features provided by other frameworks. Signals and slots are made possible by Qt's meta-object system.| doc.qt.io