Question 1

Following syntax-directed translation scheme is used with a shift reduction (bottom up) parser that perform the action in braces immediately after a reduction by the corresponding production
A ->aB {print "(1)" A -> c {print "1"),
B ->Ab {print *2"}.
When parser is aaacbbb, then string printed

Accepted Answer

A) 0202021 
B) 1202020 
C) 1020202 
D) None of these

Question 2

Let the class of language accepted by finite state machine be L1 and the class of languages represented by regular expressions be L2 then

Accepted Answer

A)  L1 
B)  L1>=L2 
C)  L1 U L2 = .* 
D)  L1=L2

Question 3

What is the highest type number which can be applied to the following grammar?
S ->Aa, A -> Ba, B ->abc

Accepted Answer

A) Type 0 
B) Type 1 
C) Type 2 
D) Type 3

Question 4

TM is more powerful than FSM because

Accepted Answer

A) The tape movement is confined to one direction 
B) It has no finite state control 
C) It has the capability to remember arbitrary long sequences of input symbols 
D) None of these

Question 5

Let L1 be a recursive language. Let L2 and L3 be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true?

Accepted Answer

A) L2- L1 is recursively enumerable 
B)  L1-L3 is recursively enumerable 
C) L2 intersection L1 is recursively enumerable 
D) L2 union L1 is recursively enumerable

Question 6

If L and L¯ are recursively enumerable, then L is

Accepted Answer

A) Regular 
B) Context free 
C) Context sensitive 
D) Recursive

Question 7

Which of the following statement is wrong?

Accepted Answer

A) Any regular language has an equivalent context-free grammar. 
B) Some non-regular languages can't be generated by any context-free grammar 
C) Intersection of context free language and a regular language is always context-free 
D) All languages can be generated by context- free grammar

Question 8

The language accepted by a Push down Automata:

Accepted Answer

A) Type 0 
B) Type 1 
C) Type 2 
D) Type 3

Question 9

For two regular languages L1 = (a + b)* a and L2 = b (a + b ) *, the intersection of L1 and L2 is given by

Accepted Answer

A) (a + b ) * ab 
B) ab (a + b ) * 
C) a ( a + b ) * b 
D) b (a + b ) * a

Question 10

Which statement is true?

Accepted Answer

A) The PDA must have one accept state and one reject state 
B) The PDA must have one accept state and two reject state 
C) The PDA must have two accept state and two reject state 
D) There is no reject state in the PDA.

Question 11

Which of the following problem is undecidable?

Accepted Answer

A) Membership problem for CFL 
B) Membership problem for regular sets 
C) Membership problem for CSL 
D) Membership problem for type 0 languages

Question 12

The following CFG is in S ? aBB**spaceB ? bAA**spaceA ? a**spaceB ? b

Accepted Answer

A) Chomsky normal form but not strong Chomsky normal form 
B) Weak Chomsky normal form but not Chomsky normal form 
C) Strong Chomsky normal form 
D) Greibach normal form

Question 13

Pumping lemma is generally used for proving that

Accepted Answer

A) Given grammar is regular 
B) Given grammar is not regular 
C) Whether two given regular expressions are equivalent or not 
D) None of these

Question 14

Match all items in Group 1 with correct options from those given in Group 2. List I List II**spaceP. Regular Expression
1) Syntax analysis**spaceQ. Push down automata
2) Code Generation**spaceR. Dataflow analysis
3) Lexical analysis**spaceS. Register allocation
4) Code optimization

Accepted Answer

A) P-4, Q-1, R-2, S-3 
B) P-3, Q-1, R-4, S-2 
C) P-3, Q-4, R-1, S-2 
D) P-2, Q-1, R-4, S-3

Question 15

Consider the following statements
I. Recursive languages are closed under complementation
II. Recursively enumerable languages are closed under union
III. Recursively enumerable languages are closed under complementation
Which of the above statement are TRUE?

Accepted Answer

A) I only 
B) I and II 
C) I and III 
D) II and III

Question 16

All NonNull words of the CFL can be generated by the corresponding CFG which is in CNF i.e the grammar in CNF will generate the same language except the:

Accepted Answer

A) String 
B) Regular language 
C) Null string 
D) None of the above

Question 17

Which of the following denotes Chomskianhiearchy?

Accepted Answer

A) REG ? CFL ? CSL ? type0 
B) CFL ? REG ? type0 ? CSL 
C) CSL ? type0 ? REG ? CFL 
D) CSL ? CFL ? REG ? type0

Question 18

Let S and T be language over ={a,b} represented by the regular expressions (a+b*)* and (a+b)*, respectively. Which of the following is true?

Accepted Answer

A) ScT (S is a subset of T) 
B) TcS (T is a subset of S) 
C) S=T 
D) SnT=Ø

Question 19

If PCP is decidable then MPCP is

Accepted Answer

A) Decidable 
B) Undecidable 
C) Can't Say 
D) None of the

Question 20

The PDA is called non-deterministic PDA when there are more than one out going edges from……… state:

Accepted Answer

A) START or READ 
B) POP or REJECT 
C) READ or POP 
D) PUSH or POP

Exam 2: Formal Languages and Automata Theory: Part B

Following syntax-directed translation scheme is used with a shift reduction (bottom up) parser that perform the action in braces immediately after a reduction by the corresponding production A ->aB {print "(1) " A -> c {print "1") , B ->Ab {print *2"}. When parser is aaacbbb, then string printed

Let the class of language accepted by finite state machine be L₁ and the class of languages represented by regular expressions be L₂ then

What is the highest type number which can be applied to the following grammar? S ->Aa, A -> Ba, B ->abc

TM is more powerful than FSM because

Let L₁ be a recursive language. Let L₂ and L₃ be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true?

If L and L¯ are recursively enumerable, then L is

Which of the following statement is wrong?

The language accepted by a Push down Automata:

For two regular languages L₁ = (a + b) * a and L₂ = b (a + b ) *, the intersection of L₁ and L₂ is given by

Which statement is true?

Which of the following problem is undecidable?

The following CFG is in S ? aBBspaceB ? bAAspaceA ? a**spaceB ? b

Pumping lemma is generally used for proving that

Match all items in Group 1 with correct options from those given in Group 2. List I List IIspaceP. Regular Expression 1) Syntax analysisspaceQ. Push down automata 2) Code GenerationspaceR. Dataflow analysis 3) Lexical analysisspaceS. Register allocation 4) Code optimization

Consider the following statements I. Recursive languages are closed under complementation II. Recursively enumerable languages are closed under union III. Recursively enumerable languages are closed under complementation Which of the above statement are TRUE?

All NonNull words of the CFL can be generated by the corresponding CFG which is in CNF i.e the grammar in CNF will generate the same language except the:

Which of the following denotes Chomskianhiearchy?

Let S and T be language over ={a,b} represented by the regular expressions (a+b) and (a+b) *, respectively. Which of the following is true?

If PCP is decidable then MPCP is

The PDA is called non-deterministic PDA when there are more than one out going edges from……… state:

Exam 2: Formal Languages and Automata Theory: Part B

Following syntax-directed translation scheme is used with a shift reduction (bottom up) parser that perform the action in braces immediately after a reduction by the corresponding production A ->aB {print "(1) " A -> c {print "1") , B ->Ab {print *2"}. When parser is aaacbbb, then string printed

Let the class of language accepted by finite state machine be L1 and the class of languages represented by regular expressions be L2 then

What is the highest type number which can be applied to the following grammar? S ->Aa, A -> Ba, B ->abc

TM is more powerful than FSM because

Let L1 be a recursive language. Let L2 and L3 be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true?

If L and L¯ are recursively enumerable, then L is

Which of the following statement is wrong?

The language accepted by a Push down Automata:

For two regular languages L1 = (a + b) * a and L2 = b (a + b ) *, the intersection of L1 and L2 is given by

Which statement is true?

Which of the following problem is undecidable?

The following CFG is in S ? aBB**spaceB ? bAA**spaceA ? a**spaceB ? b

Pumping lemma is generally used for proving that

Match all items in Group 1 with correct options from those given in Group 2. List I List II**spaceP. Regular Expression 1) Syntax analysis**spaceQ. Push down automata 2) Code Generation**spaceR. Dataflow analysis 3) Lexical analysis**spaceS. Register allocation 4) Code optimization

Consider the following statements I. Recursive languages are closed under complementation II. Recursively enumerable languages are closed under union III. Recursively enumerable languages are closed under complementation Which of the above statement are TRUE?

All NonNull words of the CFL can be generated by the corresponding CFG which is in CNF i.e the grammar in CNF will generate the same language except the:

Which of the following denotes Chomskianhiearchy?

Let S and T be language over ={a,b} represented by the regular expressions (a+b*) * and (a+b) *, respectively. Which of the following is true?

If PCP is decidable then MPCP is

The PDA is called non-deterministic PDA when there are more than one out going edges from……… state:

Let the class of language accepted by finite state machine be L₁ and the class of languages represented by regular expressions be L₂ then

Let L₁ be a recursive language. Let L₂ and L₃ be languages that are recursively enumerable but not recursive. Which of the following statements is not necessarily true?

For two regular languages L₁ = (a + b) * a and L₂ = b (a + b ) *, the intersection of L₁ and L₂ is given by

The following CFG is in S ? aBBspaceB ? bAAspaceA ? a**spaceB ? b

Match all items in Group 1 with correct options from those given in Group 2. List I List IIspaceP. Regular Expression 1) Syntax analysisspaceQ. Push down automata 2) Code GenerationspaceR. Dataflow analysis 3) Lexical analysisspaceS. Register allocation 4) Code optimization

Let S and T be language over ={a,b} represented by the regular expressions (a+b) and (a+b) *, respectively. Which of the following is true?