Compiler Design Test 2

Result

Compiler Design Test 2

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Which of the following statement is true?

A
SLR parser is more powerful than LALR parser

B
The parsers canonical LR and LALR have the same power

C
Canonical LR parser is more powerful than LALR parser

D
LALR parser is more important than canonical LR parser

Solution

Concept:
Among all the parsers Canonical LR (CLR) parser is most power full than other parsers.
Increasing order of parser’s power: LL(1) < SLR < LALR < CLR
Explanation:
From above order we can say that CLR is the most power full parser, hence option 3 is the correct answer.
Question 2
1 / -0

Consider the following grammar in which start symbol = {S}, Non Terminal symbol = {A, B, C, D} and Terminal symbol = {a, p, q, r, s, ϵ}.
S → A B | p r C | C q
A → a S | C
B → q | ϵ
C → r | ϵ
D → B s | ϵ
Find the number of terminals in the FIRST(S)?

A
3

B
4

C
5

D
6

Solution

FIRST(S) = {FIRST(A) ∪ p ∪ FIRST(C)
FIRST(A) = a ∪ FIRST(C)
FIRST(C) = {r ∪ ϵ}
NOW, FIRST(S) = {a ∪ p ∪ r ∪ q ∪ FIRST(B)
FIRST(B) = q ∪ ϵ ∪ FIRST(C)
FIRST(S) = {a ∪ p ∪ r ∪ q ∪ ϵ}
the number of terminals in the FIRST(S) is 5.

Question 3

1 / -0

Input taken by semantic analyzer and output produces by semantic analyzer are

Token stream, syntax tree

Character stream, token stream

Syntax tree, intermediate representation

Syntax tree, syntax tree

Solution

Phases of Compiler	Input	Output
Lexical Analyzer	Character stream	Token stream
Syntax Analyzer	Token stream	Syntax tree
Semantic Analyzer	Syntax tree	Syntax tree
Intermediate Code Generator	Syntax tree	Intermediate representation
Machine-Independent Code Optimizer	Intermediate representation	Intermediate representation
Code Generator	Intermediate representation	Target-machine code
Machine-Dependent Code Optimizer	Target-machine code	Target-machine code

Question 4
1 / -0

Which of the following statements is/are true about the parser?
A. Leftmost derivation is used for Bottom-up parser.
B. Rightmost in reverse derivation is used by LL parser.

A
Only A

B
Only B

C
Both A and B

D
Neither A nor B

Solution

Parser
Derivation
LR parsers or Bottom-up Parsers
Rightmost reverse Derivation
LL parsers or Top-down Parsers
Leftmost Derivation
Therefore, both statements are false. Hence option 4 is correct
Question 5
1 / -0

Consider the below given augmented grammar:
A' → A
A → a B b | num
B → B c A | A | @
If C0 = CLOSURE ({[A' → •A]}) then the number of items in the set GOTO (C0, a) is ______

A
6-6

B
64-61

C
67-66

D
69-62

Solution

Table: GOTO (C0, a)
CLOSURE ({[A' → •A]})
A' → .A
A → .a B b | num

GOTO (C0, a)
A → a.B b | num
B → .B c A
B → .A
A → .aB b
A → .num
B → .@
∴ number of items in the set GOTO (C0, a) is 6
Question 6
1 / -0

Consider the following grammar:
S → aS'
S' → aS' | ϵ
Above grammar is
I. not left recursive
II. not ambiguous
III. LL(1)
Which of the following is/are true?

A
Only I

B
Only I and II

C
Only II and III

D
All of the above
Solution
Statement I:
S → aS' \\ right recursive
S' → aS' | ϵ \\ right recursive
Therefore given grammar is not left recursive
Statement II:
Two parse trees cannot be generated for any string in the given grammar and hence it is not ambiguous.
Statement III:
A grammar G is LL(1) iff. for all non-terminals A, each distinct pair of productions A → β and A → γ satisfy the condition FIRST(β) $\cap$ FIRST(γ) = φ.
A grammar G is LL(1) iff. for each set of productions A→α₁ |α₂ |···|α_n:
FIRST(α₁), FIRST(α₂), ..., FIRST(α_n) are all pairwise disjoint
If α_i ⇒ *ε then FIRST(α_j) $\cap$ FOLLOW(A) = φ, ∀1 ≤ j ≤ n, i $\neq$ j
Grammar is LL(1):
NON- TERMINAL
FIRST
FOLLOW
S
a
$
S’
a, ϵ
$

Although FIRST(S') has ϵ, FIRST(S') and FOLLOW(S') doesn't contain any common element. Therefore a cell in parsing table will contain at most one entry in it and hence it is LL(1)
Question 7
1 / -0

Consider the grammar given below:
X → Px
P → RQ | R
Q → y | w | ε
R → z | ε
Let x, y, z, w, and $ be indexed as follows:
X
y
Z
w
$
1
2
3
4
5

Compute the FOLLOW set of the non-terminal R and write the index values for the symbols in the FOLLOW set in the ascending order. (For example, if the FOLLOW set is {x, y, z, w, $}, then the answer should be 12345)

A
124-124

B
1244-1241

C
1247-1246

D
1249-1242

Solution

P → RQ | R
FOLLOW of R is FIRST of Q
FIRST of Q is {y, w, ϵ}
Since epsilon cannot be follow
FOLLOW of R from is FOLLOW of P
FOLLOW of P is {x}
∴ FOLLOW of R is {x, y, w}
From table, x = 1, y = 2 and z = 4
Therefore 124 is the answer.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Parser	Derivation
LR parsers or Bottom-up Parsers	Rightmost reverse Derivation
LL parsers or Top-down Parsers	Leftmost Derivation

NON- TERMINAL	FIRST	FOLLOW
S	a	$
S’	a, ϵ	$

Compiler Design Test 2

Result

Compiler Design Test 2

Score

-

Rank

-

SHARING IS CARING

Question 1

SLR parser is more powerful than LALR parser

The parsers canonical LR and LALR have the same power

Canonical LR parser is more powerful than LALR parser

LALR parser is more important than canonical LR parser

Solution

Question 2

3

4

5

6

Solution

Question 3

Token stream, syntax tree

Character stream, token stream

Syntax tree, intermediate representation

Syntax tree, syntax tree

Solution

Question 4

Only A

Only B

Both A and B

Neither A nor B

Solution

Question 5

6-6

64-61

67-66

69-62

Solution

Question 6

Only I

Only I and II

Only II and III

All of the above

Solution

Question 7

124-124

1244-1241

1247-1246

1249-1242

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.