Since we need to create different versions of the same algorithms using different type, we should again make use of C++ templates. This will allow us to write the code one time, and reuse it for any factory type we need.
First we need to factor out the types that are different. If you look at all three classes, you will see that three types are different. The enumeration type, the builder type, and the return type for the Build method is different in all three classes. If we make those template parameters, we can reuse the same code instead of recreating the same class three times. Here is how we should refactor our code:
//M5Factory.h template<typename EnumType, typename BuilderType, typename ReturnType> class M5Factory ...
