Qt is a powerful framework for building desktop application user interfaces. However, when you need information on how to achieve a particular goal, it is sometimes difficult to gather it. It can be frustrating to feel that the solution is close at hand, yet things don't work properly.
Data in a C++ program flows from a source, gets modified multiple times and ends up as something entirely different. During processing, the data may change type, reflecting its changing nature. As programmers, we design a type system that reflects the semantic meaning of the data, its structure and its current state. Ideally, the C++ type system should give us all the vocabulary we need.