Question

Complement of a DFA can be obtained by

(a) making starting state as final state.

(b) no trival method.

(c) making final states non-final and non-final to final.

(d) make final as a starting state.

I have been asked this question in an interview for internship.

This question is from Union, Intersection & Complement topic in section Finite Automata of Automata Theory

Answer 1

Right answer is (c) making final states non-final and non-final to final.

Easiest explanation: String accepted in previous DFA will not be accepted and non accepting string will be accepted .