Automata Theory Multiple Choice Question & Answers (MCQs) set-16

1. If L1, L2 are regular and op(L1, L2) is also regular, then L1 and L2 are said to be ____________ under an operation op.
a) open
b) closed
c) decidable
d) none of the mentioned

2. Suppose a regular language L is closed under the operation halving, then the result would be:
a) 1/4 L will be regular
b) 1/2 L will be regular
c) 1/8 L will be regular
d) Al of the mentioned

3. If E=F+G;
Er=?
a) Fr+Gr
b) (F+G)r
c) Both (a) and (b)
d) None of the mentioned
4. With reference to Automaton to Regular Expression Conversion, for each of the n rounds, where n is the number of states of DFA, we can _________ the size of the regular expression constructed.
a) double
b) triple
c) quadruple
d) none of the mentioned
5. Which of the following are not meant to specify a regular language?
a) Regular Expression
b) DFA
c) NDFA and epsilon-NFA
d) All of the mentioned
6. Which of the expression is appropriate?
For production p: a->b where a?V and b?_______
a) V
b) S
c) (V+?)*
d) V+ ?
7. An expression is mentioned as follows. Figure out number of incorrect notations or symbols, such that a change in those could make the expression correct.
L(G)={w in T*|S?*w}
a) 0 Errors
b) 1 Error
c) 2 Error
d) Invalid Expression
8. Which of the following languages are most suitable for implement context free languages ?
a) C
b) Perl
c) Assembly Language
d) None of the mentioned
9. __________ is the acyclic graphical representation of a grammar.
a) Binary tree
b) Oct tree
c) Parse tree
d) None of the mentioned

10. Grammar is checked by which component of compiler
a) Scanner
b) Parser
c) Semantic Analyzer
d) None of the mentioned

11. To derive a string using the production rules of a given grammar, we use:
a) Scanning
b) Parsing
c) Derivation
d) All of the mentioned

12. Choose the correct option:
Statement 1: Recursive Inference, using productions from head to body.
Statement 2: Derivations, using productions from body to head.
a) Statement 1 is true and Statement 2 is true
b) Statement 1 and Statement 2, both are false
c) Statement 1 is true and Statement 2 is false
d) Statement 2 is true and Statement 1 is true

13. Which of the following statements are correct for a concept called inherent ambiguity in CFL?
a) Every CFG for L is ambiguous
b) Every CFG for L is unambiguous
c) Every CFG is also regular
d) None of the mentioned
14. Which of the following is true for a predictive parser?
a) Recursive Descent parser
b) no backtracking
c) Recursive Descent parser and no backtracking
d) None of the mentioned
15. The original YACC as written in __________ language
a) R programming language
b) C programming language
c) B programming language
d) None of the mentioned