GATE CSE Compiler Design PYQs & Answers — Page 5

Questions 41–50 of 55. Imported answers require independent review unless marked reviewed.

Consider the following grammar.

The number of reduction steps taken by a bottom-up parser while accepting the string

is ________.

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Consider the productions A → PQ and A → XY. Each of the five non-terminals A, P, Q, X, and Y has two attributes: s is a synthesized attribute, and i is an inherited attribute. Consider the following rules. Rule 1: P.i = A.i + 2, Q.i = P.i + A.i, and A.s = P.s + Q.s. Rule 2: X.i = A.i + Y.s and Y.i = X.s + A.i. Which one of the following is TRUE?

Your answerChoose one option.

Both Rule 1 and Rule 2 are L-attributed.

Only Rule 1 is L-attributed.

Only Rule 2 is L-attributed.

Neither Rule 1 nor Rule 2 is L-attributed.

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Which one of the following kinds of derivation is used by LR parsers?

Your answerChoose one option.

Leftmost

Leftmost in reverse

Rightmost

Rightmost in reverse

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Consider the grammar given below:

S → Aa A → BD B → b | ε D → d | ε

Let a, b, d, and $ be indexed as follows:

a	b	d	$
3	2	1	0

Compute the FOLLOW set of the non-terminal B and write the index values for the symbols in the FOLLOW set in the descending order. (For example, if the FOLLOW set is , then the answer should be 3210)

Answer: __________.

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Consider the following grammar and the semantic actions to support the inherited type declaration attributes. Let

, and

be the placeholders for the non-terminals D, T, L or

in the following table:

Production rule	Semantic action
D → T L	.type = .type
T → int	T.type = int
T → float	T.type = float
L → , id	.type = .type; addType(id.entry, .type)
L → id	addType(id.entry, .type)

Which one of the following are the appropriate choices for

and

Your answerChoose one option.

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Consider the augmented grammar given below: S' → •S S → ⟨L⟩ | id L → L,S | S

Let I₀ = CLOSURE ({[S' → •S]}). The number of items in the set GOTO (I₀, ⟨) is: ________.

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Which one of the following statements is FALSE?

Your answerChoose one option.

Context-free grammar can be used to specify both lexical and syntax rules.

Type checking is done before parsing.

High-level language programs can be translated to different Intermediate Representations.

Arguments to a function can be passed using the program stack.

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A lexical analyzer uses the following patterns to recognize three tokens

, and

over the alphabet

Note that ‘

’ means 0 or 1 occurrence of the symbol x. Note also that the analyzer outputs the token that matches the longest possible prefix.

If the string

is processed by the analyzer, which one of the following is the sequence of tokens it outputs?

Your answerChoose one option.

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Consider the following parse tree for the expression

, involving two binary operators

and

Diagram for Computer Science and Information Technology question 38

Which one of the following is correct for the given parse tree?

Your answerChoose one option.

has higher precedence and is left associative;

is right associative

has higher precedence and is left associative;

is right associative

has higher precedence and is left associative;

is left associative

has higher precedence and is right associative;

is left associative

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Match the following according to input (from the left column) to the compiler phase (in the right column) that processes it:

(P) Syntax tree (Q) Character stream (R) Intermediate representation (S) Token stream

(i) Code generator (ii) Syntax analyser (iii) Semantic analyser (iv) Lexical analyser

Your answerChoose one option.

P → (ii), Q → (iii), R → (iv), S → (i)

P → (ii), Q → (i), R → (iii), S → (iv)

P → (iii), Q → (iv), R → (i), S → (ii)

P → (i), Q → (iv), R → (ii), S → (iii)

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GATE CSE Compiler Design PYQs

Question 24

Question 33

Question 3

Question 19

Question 36

Question 43

Question 8

Question 37

Question 38

Question 5