Regular expressions MCQs [Theory of automata]

Regular expressions MCQs in Theory of automata

Regular expressions are closed under
(a) Union
(b) Intersection
(c) Kleen star
(d) none of these

(e) All of these

Answer:

(e) All of these

Which strings are valid for Regular Expression aa(bb)*
a. bb, bbbb, bbbbbb,…
b. abb, abbbb, abbbbbb,…
c.  aabb, aabbbb, aabbb,…
d.  aabb, aabbbb, aabbbb,…

Answer:

aabb, aabbbb, aabbbb,…

Regular Expression For All Strings Starts With a defined over {a,b}
a. a(a+b)
b. a(a+b)*

c.  a*

d.  a*(a+b)*

Answer:

b. a(a+b)*

Regular Expression For All Strings Starts With ab and ends with b defined over {a,b}
a. ab(a+b)b
b. ab(a+b)* b

c.  ab* b

d.  None of these

Answer:

ab(a+b)* b

Regular Expression For All Strings having always consecutive a’s defined over {a,b}
a.  (aa+b)
b.  aa(b)*
c.  (aa+b)*
d.  None of these

Answer:

c.  (aa+b)*

Which one is correct regarding Regular Expression?
a.  We can draw FA for each regular expression

b. We can’t draw FA for some regular expression
c.  RE defines regular languages
d.  Both a and C

Answer:

d.  Both a and C

AUTOMATA THEORY MCQS

Regular expressions MCQs 

FA DFA NFA MCQs 

Examples of Regular Expression 

  1. Regular Expression for no 0 or many triples of 0’s and many 1 in the strings.
  2. RegExp for strings of one or many 11 or no 11.
  3. A regular expression for ending with abb
  4. A regular expression for all strings having 010 or 101.
  5. Regular expression for Even Length Strings defined over {a,b}
  6. Regular Expression for strings having at least one double 0 or double 1.
  7. Regular Expression of starting with 0 and having multiple even 1’s or no 1.
  8. Regular Expression for an odd number of 0’s or an odd number of 1’s in the strings.
  9. Regular Expression for having strings of multiple double 1’s or null.
  10. Regular Expression (RE) for starting with 0 and ending with 1.
  11. RE for ending with b and having zero or multiple sets of aa and bb.
  12. A regular expression of the second last symbol is 1.
  13. RE for starting with 1 having zero or multiple even 1’s.
  14. Regular Expression for multiple a’s and multiple b’s.
  15. RE for exactly single 1 many 0’s |exactly single a many b.
  16. A regular expression for strings starting with aa and ending with ba.
  17. A regular expression for the language of all consecutive even length a’s.
  18. A regular expression for the language of all odd-length strings
  19. A regular expression for the language of all even length strings but ends with aa.
  20. A regular expression for the language of an odd number of 1s.
  21. A regular expression for the language of even length strings starting with a and ending with b in theory of automata.
  22. A regular expression for the language of all even length strings but starts with a.
  23. A Regular Expression for the Language of all strings with an even number of 0’s or even number of 1’s.
  24. A regular expression for the language of all those strings end with abb.
  25. A regular expression for string having must 010 or 101.
  26. Regular expression of  strings begin with 110
    Regular expression of  strings begin and end with 110
    Regular expression of strings containing exactly three consecutive 1’s.
  27. A Regular Expression of all strings divisible by 4.
  28. A Regular Expression Strings that does not contain substring 110.

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