Q. Which of the following derivations does a top-down parser use while parsing an input string? The input is assumed to be scanned in left to right order.

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Q. Given the following expression grammar:

E -> E * F | F + E | F
F -> F - F | id

which of the following is true?

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Q. Which one of the following is True at any valid state in shift-reduce parsing?

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Q. In the context of abstract-syntax-tree (AST) and control-flow-graph (CFG), which one of the following is True?

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Q. Match the following:

List-I List-II
A. Lexical analysis 1. Graph coloring
B. Parsing 2. DFA minimization
C. Register allocation 3. Post-order traversal
D. Expression evaluation 4. Production tree

Codes:
A B C D
(a) 2 3 1 4
(b) 2 1 4 3
(c) 2 4 1 3
(d) 2 3 4 1

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Q. Among simple LR (SLR), canonical LR, and look-ahead LR (LALR), which of the following pairs identify the method that is very easy to implement and the method that is the most powerful, in that order?

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Q. Consider the following grammar G.

S → F ⎪ H
F → p ⎪ c
H → d ⎪ c

Where S, F and H are non-terminal symbols, p, d and c are terminal symbols. Which of the following statement(s) is/are correct?

S1: LL(1) can parse all strings that are generated using grammar G.
S2: LR(1) can parse all strings that are generated using grammar G.

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Q. A CFG G is given with the following productions where S is the start symbol, A is a non-terminal and a and b are terminals.

S→aS∣A
A→aAb∣bAa∣ϵ

For the correct answer in Q75, how many steps are required to derive the string and how many parse trees are there?

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Q. Some code optimizations are carried out on the intermediate code because

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Q. Which one of the following is FALSE?

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Q. One of the purposes of using intermediate code in compilers is to

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Q. Consider the grammar rule E → E1 - E2 for arithmetic expressions. The code generated is targeted to a CPU having a single user register. The subtraction operation requires the first operand to be in the register. If E1 and E2 do not have any common sub expression, in order to get the shortest possible code

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Q. Consider the intermediate code given below:

1. i = 1
2. j = 1
3. t1 = 5 * i
4. t2 = t1 + j
5. t3 = 4 * t2
6. t4 = t3
7. a[t4] = –1
8. j = j + 1
9. if j <= 5 goto(3)
10. i = i + 1
11. if i < 5 goto(2)

The number of nodes and edges in the control-flow-graph constructed for the above code, respectively, are

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Q. Consider the following code segment.

x = u - t;
y = x * v;
x = y + w;
y = t - z;
y = x * y;

The minimum number of total variables required to convert the above code segment to static single assignment form is

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Q. Which of the following derivations does a top-down parser use while parsing an input string?
The input is assumed to be scanned in left to right order.

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Q. Which of the following statements is false ?

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Q. Consider a program P that consists of two source modules M1 and M2 contained in two different files. If M1 contains a reference to a function defined in M2, the reference will be resolved at

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Q. Consider the following statements:

(I) The output of a lexical analyzer is groups of characters.
(II) Total number of tokens in printf("i=%d, &i=%x", i, &i); are 11.
(III) Symbol table can be implementation by using array and hash table but not tree.

Which of the following statement(s) is/are correct?

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Q. Which one of the following statements is FALSE ?

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Q. A lexical analyzer uses the following patterns to recognize three tokens T1, T2, and T3 over the alphabet {a,b,c}.

T1: a?(b∣c)*a
T2: b?(a∣c)*b
T3: c?(b∣a)*c

Note that ‘x?’ 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 bbaacabc is processes by the analyzer, which one of the following is the sequence of tokens it outputs?

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