Designing Finite Automata


















How do you design a finite state machine?

How do you decide how many states you need?

Can you remember all the input (go to a new state for each input symbol)?

An approach

	1. decide what needs to be remembered
	2. make a state for each possibility
	3. add transitions
	4. set the start state
	5. set the accept states

















Design a machine that recognizes the language.
(w is a string of 0's and 1's)


	{ w | w is any string except 11 and 111 } (1.6h)


	{ w | w contains an even number of 0s,
	      	or contains exactly two 1s } (1.6l)

















Classwork
(You may work with a partner.)

Design a machine that recognizes the language.
(w is a string of 0's and 1's)


	{ w | w starts with 0 and has odd length, 
	       or starts with 1 and has even length } (1.6e)