gentlemen: I have a feeling that asBEHAVE_FACTORY is similar to asBEHAVE_CONSTRUCT, what is the difference of asBEHAVE_FACTORY with asBEHAVE_CONSTRUCT? who can give me an example ?

The factory is to reference types what the constructor is to value types.

The biggest difference is that the factory is responsible for allocating and initializing the memory for the object, whereas the constructor is only responsible for initializing the memory already allocated elsewhere.

Regards,
Andreas