ISRO Scientist/Engineer SC Computer Science 2018 — ISRO Scientist/Engineer SC 2018 · Computer Science

Consider the following program

#include <stdio.h>

int main()
{
    int x = 1;
    printf("%d", *(char *)&x);
    return 0;
}

Assuming required header files are included and if the machine in which this program is executed is little-endian, then the output will be

Consider the following declaration :

struct addr {
     char city[10];
     char street[30];
     int pin ;
};

struct {
char name[30];
int gender;
struct addr locate;
} person , *kd = &person ;

Then *(kd -> name +2) can be used instead of

If a variable can take only integral values from 0 to n, where n is an integer, then the variable can be represented as a bit-field whose width is (the log in the answers are to the base 2, and [log n] means the floor of log n)

The following C program

main()
{
    fork() ; fork() ; printf ("yes");
}

If we execute this core segment, how many times the string yes will be printed ?

Consider the following table in a relational database

 Last Name      Rank          Room       Shift
 Smith          Manager       234        Morning
 Jones          Custodian     33         Afternoon
 Smith          Custodian     33         Evening
 Doe            Clerical      222        Morning

According to the data shown in the table, which of the following could be a candidate key of the table?

A data driven machine is one that executes an instruction if the needed data is available. The physical ordering of the code listing does not dictate the course of execution. Consider the following pseudo-code:

(A) Multiply E by 0.5 to get F

(B) Add A and B to get E

(C) Add B with 0.5 to get D

(D) Add E and F to get G

(E) Add A with 10.5 to get C

Assume A, B, C are already assigned values and the desired output is G. Which of the following sequence of execution is valid?

Assume A and B are non-zero positive integers. The following code segment:

while ( A != B){
     if ( A > B ) A - = B ;
     else B - = A ; 
} 
cout << A; // printing the value of A

A language with string manipulation facilities uses the following operations. 

head(s)- returns the first character of the string s 
tail(s)- returns all but the first character of the string s 
concat(s1, s2)- concatenates string s1 with s2. 

The output of concat(head(s), head(tail(tail(s)))), where s is acbc is

In the diagram above, the inverter (NOT gate) and the AND-gates labeled 1 and 2 have delays of 9, 10 and 12 nanoseconds(ns), respectively. Wire delays are negligible. For certain values of a and c, together with certain transition of b, a glitch (spurious output) is generated for a short time, after which the output assumes its correct value. The duration of the glitch is

_______ can detect burst error of length less than or equal to degree of the polynomial and detects burst errors that affect odd number of bits.

An array A consists of n integers in locations A[0], A[1] ....A[n-1]. It is required to shift the elements of the array cyclically to the left by k places, where 1 <= k <= (n-1). An incomplete algorithm for doing this in linear time, without using another array is given below. Complete the algorithm by filling in the blanks. Assume all the variables are suitably declared.

min = n; i = 0;

while (___________) {	

     temp = A[i]; j = i;

     while (________) {

     A[j] = ________	

     j= (j + k) mod n ;

     If ( j< min ) then

         min = j;

}

A[(n + i — k) mod n] = _________

i = __________

The difference between a named pipe and a regular file in Unix is that

A class of 30 students occupy a classroom containing 5 rows of seats, with 8 seats in each row. If the students seat themselves at random, the probability that the sixth seat in the fifth row will be empty is

The domain of the function log( log sin(x) ) is

The following paradigm can be used to find the solution of the problem in minimum time: Given a set of non-negative integer, and a value K, determine if there is a subset of the given set with sum equal to K:

( G, *) is an abelian group. Then

Consider the following C code segment:

#include <stdio.h>
main()
{
    int i, j , x ;
    scanf("%d", &x);
    i = 1 ; j = 1;
    while ( i< 10 ) {
          j = j * i;
          i = i + 1;
          if (i == x) break ;
          }
 }

For the program fragment above, which of the following statements about the variables i and j must be true after execution of this program? [!(exclamation) sign denotes factorial in the answer]

Given √224r = 13r the value of radix r is

Determine the number of page faults when references to pages occur in the order - 1, 2, 4, 5, 2, 1, 2, 4. Assume that the main memory can accommodate 3 pages and the main memory already has the pages 1 and 2, with page 1 having brought earlier than page 2.(assume LRU i.e. Least-Recently-Used algorithm is applied)

Consider a system having m resources of the same type. These resources are shared by 3 processes A, B, C which have peak time demands of 3, 4, 6 respectively. The minimum value of m that ensures deadlock will never occur is

A computer has 1000 K of main memory. The jobs arrive and finish in the sequence Job 1 requiring 200 K arrives Job 2 requiring 350 K arrives Job 3 requiring 300 K arrives Job 1 finishes Job 4 requiring 120 K arrives Job 5 requiring 150 K arrives Job 6 requiring 80 K arrives Among best fit and first fit, which performs better for this sequence?

Disk requests come to a disk driver for cylinders in the order 10, 22, 20, 2, 40, 6, and 38 at a time when the disk drive is reading from cylinder 20. The seek time is 6 ms/cylinder. The total seek time, if the disk arm scheduling algorithms is first-come-first-served is

Choose the correct statement:

CFG (Context Free Grammar) is not closed under

The FSM (Finite State Machine) machine pictured in the figure above

A CFG(Context Free Grammar) is said to be in Chomsky Normal Form (CNF), if all the productions are of the form A -> BC or A -> a. Let G be a CFG in CNF. To derive a string of terminals of length x, the number of products to be used is

Incremental-Compiler is a compiler

DU-chains(Definition-Use) in compiler design

Which of the following comment about peep-hole optimization is true?

A byte-addressable computer has a memory capacity of 2m KB (kilobytes) and can perform 2n operations. An instruction involving three operands and one operator needs a maximum of:

A computer uses ternary system instead of the traditional binary system. An n bit string in the binary system will occupy

Which of the following is application of Breath First Search on the graph?

Micro program is

Given two sorted list of size m and n respectively. The number of comparisons needed the worst case by the merge sort algorithm will be

A hash table with 10 buckets with one slot per bucket is depicted here. The symbols, S1 to S7 are initially entered using a hashing function with linear probing. The maximum number of comparisons needed in searching an item that is not present is

The running time of an algorithm is given by

T(n) = T(n-1) + T(n-2) — T(n-3), if n > 3
     = arbitrary initial values, for n ≤ 3

Then what should be the relation between T(1), T(2) and T(3), so that the order of the algorithm is constant ?

The number of edges in a regular graph of degree d and n vertices is

Perform window to viewport transformation for the point (20, 15). Assume that (Xwmin, Ywmin) is (0,0); (Xwmax, Ywmax) is (100,100); (Xvmin, Yvmin) is (5,5); (Xvmax, Yvmax) is (20,20). The value of x and y in the viewport is

Given relations R(w,x) and S(y,z), the result of

SELECT DISTINCT w, x
FROM R, S

Is guaranteed to be same as R, if

For a database relation R(a,b,c,d) where the domains of a, b, c and d include only atomic values, only the following functional dependencies and those that can be inferred from them hold a → c b → d The relation is in

Consider the set of relations given below and the SQL query that follows

Students : (Roll number, Name, Date of birth)
Courses: (Course number, Course name, instructor)
Grades: (Roll number, Course number, Grade)
SELECT DISTINCT Name
FROM Students, Courses, Grades
WHERE Students.Roll_number = Grades.Roll_number
       AND Courses.Instructor =Sriram
       AND Courses.Course_number = Grades.Course_number
       AND Grades.Grade = A

Which of the following sets is computed by the above query?

Consider the following C++ program

int a (int m)
{ return ++m; }
int b(int &m)
{ return ++m; }
int c(char &m)
{ return ++m; }
void main ()
{
    int p = 0, q = 0, r = 0;
    p += a(b(p));
    q += b(a(q));
    r += a(c(r));
    cout << p << q << r;
}

Assuming the required header files are already included, the above program

Station A uses 32 byte packets to transmit messages to Station B using a sliding window protocol. The round trip delay between A and B is 80 ms and the bottleneck bandwidth on the path between A and B is 128 kbps. What is the optimal window size that A should use?

Assuming that for a given network layer implementation, connection establishment overhead is 100 bytes and disconnection overhead is 28 bytes. What would be the minimum size of the packet the transport layer needs to keep up, if it wishes to implement a datagram service above the network layer and needs to keep its overhead to a minimum of 12.5%. (Ignore transport layer overhead)

In cryptography, the following uses transposition ciphers and the keyword is LAYER. Encrypt the following message. (Spaces are omitted during encryption) WELCOME TO NETWORK SECURITY !

In a particular program, it is found that 1% of the code accounts for 50% of the execution time. To code a program in C++, it takes 100 man-days. Coding in assembly language is 10 times harder than coding in C++, but runs 5 times faster. Converting an existing C++ program into an assembly language program is 4 times faster. To completely write the program in C++ and rewrite the 1% code in assembly language, if a project team needs 13 days, the team consists

In unit testing of a module, it is found that for a set of test data, at the maximum 90% of the code alone were tested with the probability of success 0.9. The reliability of the module is

In a file which contains 1 million records and the order of the tree is 100, then what is the maximum number of nodes to be accessed if B+ tree index is used?

A particular disk unit uses a bit string to record the occupancy or vacancy of its tracks, with 0 denoting vacant and 1 for occupied. A 32-bit segment of this string has hexadecimal value D4FE2003. The percentage of occupied tracks for the corresponding part of the disk, to the nearest percentage is

Which of the following is dense index?

In E-R model, Y is the dominant entity and X is subordinate entity

Immunity of the external schemas (or application programs) to changes in the conceptual schema is referred to as:

The set of attributes X will be fully functionally dependent on the set of attributes Y if the following conditions are satisfied.

Let us assume that transaction T1 has arrived before transaction T2. Consider the schedule

S=r1(A); r2(B) ; w2(A); w1(B) 

Which of the following is true?

The time complexity of computing the transitive closure of binary relation on a set of n elements is known to be

Given a binary-max heap. The elements are stored in an arrays as 25, 14, 16, 13, 10, 8, 12. What is the content of the array after two delete operations?

The Functions Point (FP) metric is

The lower degree of cohesion is kind of

What is the output of the following program ?

main (){
int x = 2, y = 5;
if(x < y) return (x = x + y);
else printf ("z1");
printf("z2");
}

The Operating System of a computer may periodically collect all the free memory space to form contiguous block of free space. This is called:

Any set of Boolean operators that is sufficient to represent all Boolean expressions is said to be complete. Which of the following is not complete?

Consider a singly linked list of the form where F is a pointer to the first element in the linked list and L is the pointer to the last element in the list. The time of which of the following operations depends on the length of the list?

A particular BNF definition for a “word” is given by the following rules.

<word> ::= <letter> | <letter><charpair> | <letter><intpair>

<charpair> ::= <letter><letter> | <charpair><letter><letter>

<intpair> ::= <integer><integer> | <intpair><integer><integer>

<letter> ::= a | b | c | ... | y | z

<integer> ::= 0 | 1 | 2 | ... | 9

Which of the following lexical entries can be derived from <word>? I. pick II. picks III. c44

Of the following, which best characterizes computers that use memory-mapped I/O?

Of the following sorting algorithms, which has an O(n log n) worst-case running time that is least dependent on the initial ordering of the input?

Processes P1 and P2 have a producer-consumer relationship, communicating by the use of a set of shared buffers.

P1: repeat
    Obtain an empty buffer
    Fill it
    Return a full buffer
    forever
P2: repeat
    Obtain a full buffer
    Empty it
    Return an empty buffer
    forever

Increasing the number of buffers is likely to do which of the following?

I. Increase the rate at which requests are satisfied (throughput)

II. Decrease the likelihood of deadlock

III. Increase the ease of achieving a correct implementation

In multi-programmed systems, it is advantageous if some programs such as editors and compilers can be shared by several users. Which of the following must be true of multi-programmed systems in order that a single copy of a program can be shared by several users?

I. The program is a macro

II. The program is recursive

III. The program is reentrant

Let P be a procedure that for some inputs calls itself (i.e. is recursive). If P is guaranteed to terminate, which of the following statement(s) must be true?

I.   P has a local variable
II.  P has an execution path where it does not call itself
III. P either refers to a global variable or has at least one parameter

Consider the following C program

#include <stdio.h>
int main()
{
float sum = 0.0, j =1.0, i = 2.0; 
while(i/j > 0.001) {
    j = j + 1;
    sum = sum + i/j;
    printf ( "%f\n", sum );
    }
}

How many lines of output does this program produce?

A particular parallel program computation requires 100 sec when executed on a single processor. If 40% of this computation is inherently sequential (i.e. will not benefit from additional processors), then theoretically best possible elapsed times of this program running with 2 and 4 processors, respectively, are

Consider the following C code segment

int f(int x) { if (x < 1) return 1; else return (f(x-1) + g(x)); }

int g(int x) { if (x < 2) return 2; else return (f(x-1) + g(x/2)); }

Of the following, which best describes the growth of f(x) as a function of x?

For a multi-processor architecture, In which protocol a write transaction is forwarded to only those processors that are known to possess a copy of newly altered cache line ?

Avalanche effect in cryptography

In neural network, the network capacity is defined as

Cloaking is a search engine optimization (SEO) technique. During cloaking

What is one advantage of setting up a DMZ(Demilitarized Zone) with two firewalls?

Which one of the following algorithm is not used in asymmetric key cryptography?

A doubly linked list is declared as

struct Node {
    int Value;
    struct Node *Fwd;
    struct Node *Bwd;
};

Where Fwd and Bwd represent forward and backward link to the adjacent elements of the list. Which of the following segments of code deletes the node pointed to by X from the doubly linked list, if it is assumed that X points to neither the first nor the last node of the list?

If Tree-1 and Tree-2 are the trees indicated below :

Which traversals of Tree-1 and Tree-2, respectively, will produce the same sequence?