I often get confused about the different types of C++ casts:
- dynamic_cast can be used for “upcasting” or “downcasting”
Upcasting:Â Â Â A* pA = dynamic_cast<A*>(pB)Â when B inherits from A
Downcasting:Â B* pB = dynamic_cast<B*>(pA)Â when B inherits from A
- static_cast conversions are not as safe as dynamic_cast conversions, because static_cast does no run-time type check, while dynamic_cast does.
- A dynamic_cast to an ambiguous pointer will fail, while a static_cast returns as if nothing were wrong; this can be dangerous.
- Although dynamic_cast conversions are safer, dynamic_cast only works on pointers or references, and the run-time type check is an overhead. (http://msdn.microsoft.com/en-us/library/5f6c9f8h%28v=VS.100%29.aspx)
- Allows any pointer to be converted into any other pointer type. Also allows any integral type to be converted into any pointer type and vice versa. (http://msdn.microsoft.com/en-us/library/e0w9f63b.aspx)