A state machine that is either DFA or NFA: is it possible?
Any piece of code can never be non-deterministic (a non-deterministic process can &quot;multiply itself&quot; by a constant factor every step, and obviously computers can't just multiply by their own free will).
Hence it is a DFA.

Also, your lexer will start always at the initial state $s_0$, and from it, depending on what it reads - it moves to different states.