GATE-CS-2017 (Set 2)

Question 31

Which of the following statements about the parser is/are correct?

I. Canonical LR is more powerful than SLR.
II. SLR is more powerful than LALR.
III. SLR is more powerful than canonical LR.

• I only
• II only
• III only
• II and III only

Question 32

Consider a quadratic equation x² - 13x + 36 = 0 with coefficients in a base b. The solutions of this equation in the same base b are x = 5 and x = 6. Then b = ______.
Note: This question appeared as Numerical Answer Type in GATE.

• 6
• 7
• 8
• 9

Question 33

The minimum number of ordered pairs that need to be added to R to make (X, R) a lattice is _____.
Note: This question appeared as Numerical Answer Type.

• 0
• 1
• 2
• 3

Question 34

Which of the following is/are shared by all the threads in a process?

I. Program Counter

II. Stack

III. Address space

IV. Registers

• I and II only
• III only
• IV only
• III and IV only

Question 35

Consider the following function implemented in C:

void printxy(int x, int y)
{
    int *ptr;
    x = 0;
    ptr = &x;
    y = *ptr;
    *ptr = 1;
    printf("%d,%d", x, y);
}

The output of the printxy(1,1) is

• 0,0
• 0,1
• 1,0
• 1,1

Question 36

A system shares 9 tape drives. The current allocation and maximum requirement of tape drives for 3 processes are shown below: Which of the following best describes the current state of the system?

• Safe, Deadlocked
• Safe, Not Deadlocked
• Not Safe, Deadlocked
• Not Safe, Not Deadlocked

Question 37

The read access times and the hit ratios for different caches in a memory hierarchy are as given below: The read access time of main memory in 90 nanoseconds. Assume that the caches use the referred-word-first read policy and the writeback policy. Assume that all the caches are direct mapped caches. Assume that the dirty bit is always 0 for all the blocks in the caches. In execution of a program, 60% od memory reads are for instruction fetch and 40% are for memory operand fetch. The average read access time in nanoseconds (up to 2 decimal places) is _________
Note: This question appeared as Numerical Answer Type.

• 2.74
• 4.72
• 3.10
• 2.67

Question 38

Consider the C program fragment below which is meant to divide x by y using repeated subtractions. The variable x, y, q and r are all unsigned int.

while(r >= y)
{
r = r - y;
q = q + 1;
}

Which of the following conditions on the variables x, y, q and r before the execution of the fragment will ensure that the loop terminates in a state satisfying the condition x == (y*q + r)?

• ( q == r ) && ( r == 0)
• ( x > 0 ) && ( r == x ) && ( y > 0 )
• ( q == 0 ) && ( r == x ) && ( y > 0 )
• ( q == 0 ) && ( y > 0 )

Question 39

Let δ denote the transition function and α denoted the extended transition function of the ε-NFA whose transition table is given below: Then, α (q2,aba) is

• Ø
• {q1, q2, q3}
• {q0, q1, q2}
• {q0, q2, q3}

Question 40

Consider the following expression grammar G.

E -> E - T | T
T -> T + F | F
F -> (E) | id

Which of the following grammars are not left recursive, but equivalent to G.

A)
E -> E - T | T
T -> T + F | F
F -> (E) | id

B)
E -> TE\'
E\' -> -TE\' | ε
T -> T + F | F
F -> (E) | id

C)
E -> TX
X -> -TX | ε
T -> FY
Y -> +FY | ε
F -> (E) | id

D)
E -> TX | (TX)
X -> -TX | +TX | ε
T -> id

• A
• B
• C
• D