A cs question i know but no one is replying there and i need urgent help !!!!

Draw deterministic finite automata of the following languages over alphabets {a, b} and also give regular expression.

i. The language of all strings containing even number of a’s and each a is followed by at least one b.

Question

A cs question i know but no one is replying there and i need urgent help !!!!

Draw deterministic finite automata of the following languages over alphabets {a, b} and also give regular expression.

i.	The language of all strings containing even number of a’s and each a is followed by at least one b.

anonymous · Answer

it is a question of theory of automata :S

anonymous · Answer

cool ! I havent seen these automata for about 20 years !
I hope they didn't change since back in the day.
Here is what I remember.

The regular expression (assuming it is allowed to accept an emptys string - otherwise the start at the end should be a plus):

(ab+ab+)*

|dw:1315145891068:dw|