Can a finite state machine transition to a previous state?
state-machine
Solution
Yes, many practical FSMs will in fact do this. Consider an FSM that identifies valid strings of number separated by one or more spaces. This would start in the "digit" state and at some point transition to the "space" state from which it might well transition back to the "digit" state.
Problem
I know that a FSM can transition to the next state and even to the current state, i.e. a state that transitions to itself, but is it legal to have a state transition to a previous state (state C transition to state B)?