The UML Statechart Diagram is a powerful tool for specifying the dynamic behavior of reactive objects (objects that respond to events sent from other objects). Implementing a simple Moore State Model – a state model with actions only on state entry – is fairly easy. The UML Statechart Diagram, however, extends Moore state machines to offer many advanced features that allow developers to model more complex behavior in a compact form. Though convenient, these features can be quite daunting to new users. This paper introduces a set of Standard C++ classes that implement UML Statechart Diagrams associated with UML classes.