What is the difference between functional and behavioural models in sofrware engineering? what are examples of each?

All behavioural models really do is describe the control structure of a system. This can be things like:

All functional models really do is describe the computational structure of the system. On the other hand, this system – even though it may have many Use Cases – should only have one functional model, yet this may be composed of many functional diagrams.

the difference is right there dont you see it