# Parsing

 Question 1
Consider the following augmented grammar with $\{ \#, @, <, >, a, b, c \}$ as the set of terminals.

$\begin{array}{l} S' \rightarrow S \\ S \rightarrow S \# cS \\ S \rightarrow SS \\ S \rightarrow S @ \\ S \rightarrow < S > \\ S \rightarrow a \\ S \rightarrow b \\ S \rightarrow c \end{array}$

Let $I_0 = \text{CLOSURE}(\{S' \rightarrow \bullet S\})$. The number of items in the set $\text{GOTO(GOTO}(I_0 \lt ), \lt )$ is ___________
 A 6 B 7 C 8 D 9
GATE CSE 2021 SET-2   Compiler Design
Question 1 Explanation:
 Question 2
Consider the following C code segment:

a = b + c;
e = a + 1;
d = b + c;
f = d + 1;
g = e + f;

In a compiler, this code segment is represented internally as a directed acyclic graph (DAG). The number of nodes in the DAG is _____________
 A 11 B 6 C 5 D 10
GATE CSE 2021 SET-1   Compiler Design
Question 2 Explanation:
 Question 3
Consider the following statements.

S1: Every SLR(1) grammar is unambiguous but there are certain unambiguous grammars that are not SLR(1).
S2: For any context-free grammar, there is a parser that takes at most $O(n^3)$ time to parse a string of length n.

Which one of the following options is correct?
 A S1 is true and S2 is false B S1 is false and S2 is true C S1 is true and S2 is true D S1 is false and S2 is false
GATE CSE 2021 SET-1   Compiler Design
Question 3 Explanation:
 Question 4
A grammar is defined as
$A \rightarrow B C$
$B \rightarrow x \mid B x$
$C \rightarrow B \mid D$
$D \rightarrow y \mid Ey$
$E \rightarrow z$
The non terminal alphabet of the grammar is
 A $\{A, B, C, D, E\}$ B $\{B, C, D, E\}$ C $\{A, B, C, D, E,x,y,z\}$ D $\{x,y,z\}$
ISRO CSE 2020   Compiler Design
Question 4 Explanation:
 Question 5
A given grammar is called ambiguous if
 A two or more productions have the same non-terminal on the left hand side B a derivation tree has more than one associated sentence C there is a sentence with more than one derivation tree corresponding to it D brackets are not present in the grammar
ISRO CSE 2020   Compiler Design
Question 5 Explanation:
 Question 6
Given the grammar
$s \rightarrow T^{*} S \mid T$
$T \rightarrow U+T \mid U$
$U \rightarrow a \mid b$
Which of the following statements is wrong?
 A Grammar is not ambiguous B Priority of + over * is ensured C Right to left evaluation of * and + happens D None of these
ISRO CSE 2020   Compiler Design
Question 6 Explanation:
 Question 7
Consider the following grammar.

$S\rightarrow aSB|d$
$B\rightarrow b$

The number of reduction steps taken by a bottom-up parser while accepting the string $aaadbbb$ is___________.
 A 5 B 6 C 7 D 8
GATE CSE 2020   Compiler Design
Question 7 Explanation:
 Question 8
Consider the augmented grammar given below:
$S'\rightarrow S$
$S \rightarrow \lt L \gt |id$
$L \rightarrow L,S|S$

Let $I_0=CLOSURE(\{[S'\rightarrow \cdot S]\})$. The number of items in the set $GOTO(I_0,\lt)$ is __________.
 A 2 B 4 C 5 D 6
GATE CSE 2019   Compiler Design
Question 8 Explanation:
 Question 9
Consider the following given grammar:

S $\rightarrow$ Aa
A $\rightarrow$ BD
B $\rightarrow$ b|$\epsilon$
D $\rightarrow$ d|$\epsilon$ 
Let a, b, d and $be indexed as follows: Compute the FOLLOW set of the non-terminal B and write the index values for the symbols in the FOLLOW set in the descending order. (For example, if the FOLLOW set is {a, b, d,$}, then the answer should be 3210).
 A 310 B 3100 C 31 D 220
GATE CSE 2019   Compiler Design
Question 9 Explanation:
 Question 10
Which one of the following kinds of derivation is used by LR parsers?
 A Leftmost B Leftmost in reverse C Rightmost D Rightmost in reverse
GATE CSE 2019   Compiler Design
Question 10 Explanation:
There are 10 questions to complete.

### 3 thoughts on “Parsing”

1. in question no. 7 there will be b instead of d in production B
S→aSB∣d
B→b