L=set of all bit strings with even number of 1's ...Regular Expression will be .

Question

Options are

a) (0*10*1)*

b) 0*(10*10*)

c) 0*(10*1)*0*

d) 0*(10*1)*10*

 

I have doubt in b and c.which one is correct and why.?

Answer 1

Option b and d is eliminated because it doesn't produce epsilon . Epsilon has also even no of 1's.

Option a can't produce 110. so a is also eliminated.

So Ans is option C

Answer 2

Option A will accept either epsilon or a string that is ending with 1 only,It may happen that string have even no. of 1's but it is ending with 0,So it won't be right answer.

Option B will generate string having only 2 1's,so it won't be the right answer because we are looking for that solution that may generate even strings having even no. of 1's.

Option C will generate string having even no. of 1's so it will be the correct answer.

Option D will generate string having odd no. of 1's so definitely it is not going to be the right answer.

So,according to me C will be the right Regex for generating string having even no. of 1's.

Correct me if I'm wrong.