Sonali & Janata Bank Officer (IT/ICT)-2019 Exam Taker: AUST | প্রশ্ন ও সমাধান

Question 1Programming

Let x be an integer which can take a value of 0 or 1. The statement if(x==0) x=1; else x=0; is equivalent to which of the following?

a)x=1+x
b)x=1-x
c)x=x-1
d)x=1%x

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Question 2Programming

Suppose a C program has floating constant 1.414, what's the best way to convert it to a float data type?

a)(float)1.414
b)float (1.414)
c)1.414f or 1.414F
d)None of these

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Question 3Programming

Consider the following variable declarations and definitions in C:

(i) int var_9=1     (ii) int 9_var=2     (iii) int _=3

Choose the correct statement w.r.t. the above variables.

a)Both (i) and (ii) are valid
b)Only (i) is valid
c)Both (i) and (iii) are valid
d)All of these

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Question 4Programming

For a given integer, which of the following operators can be used to set and reset a particular bit respectively?

a)| and &
b)&& and ||
c)& and |
d)|| and &&

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Question 5Operating Systems

The maximum number of processes that can be in ready state in computer system with n CPU's is—

a)n
b)n²
c)2n
d)independent of n

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Question 6Algorithms

Which of the following is not a stable sorting algorithm in its typical implementation?

a)Selection Sort
b)Quick Sort
c)Merge sort
d)Insertion Sort

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Question 7Algorithms

You have to sort 1GB of data with only 100MB of available main memory. Which sorting technique will be more appropriate?

a)Heap sort
b)Insertion sort
c)Quick sort
d)Merge sort

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Question 8Algorithms

Randomized quicksort is an extension of quicksort where the pivot is chosen randomly. What is the worst-case complexity of sorting n numbers using randomized quicksort?

a)O(n)
b)O(n²)
c)O (n log n)
d)O(n!)

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Question 9Algorithms

Consider the following recursive function fun(x,y). What is the value of fun(4,3)?

int fun (int x, int y) {
    if (x==0)
        return y;
    return fun(x-1, x+y);
}

a)9
b)10
c)12
d)13

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Question 10Algorithms

The average number of key comparisons done in a successful sequential search in a list of length n is-

a)log n
b)(n+1)/2
c)(n-1)/2
d)n/2

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Question 11Operating Systems

In UNIX, processes that have finished execution but have not yet had their status collected are known as-

a)Sleeping processes
b)Stopped processes
c)Zombie processes
d)Orphan processes

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Question 12Networking

Which of the following is not a standard synchronous communication protocol?

a)PAS
b)SDLC
c)SLIP
d)SMTP

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Question 13Operating Systems

Which of the following is the major part of the time taken when accessing data on the disk?

a)Settle time
b)Rotational delay
c)Waiting time
d)Seek time

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Question 14Operating Systems

In UNIX, the login prompt can be changed by changing the content of the file-

a)gettydefs
b)crontab
c)inittab
d)init

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Question 15Operating Systems

Which of the following UNIX commands allows scheduling a program to be executed at a specified time?

a)nice
b)cron
c)date and time
d)schedule

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Question 16Programming

Which of the following programming language helps you to learn Android programming?

a)C
b)SQL
c)Java
d)Python

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Question 17Cyber Security

Which tool could be used for detecting vulnerability through SQL injection?

a)Nmap
b)Metasploit
c)Bitdefender
d)UML

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Question 18Data Structures

Which of the following data structures is non-linear type?

a)Strings
b)Lists
c)Stacks
d)None of these (correct answer)

Answer and explanation

Correct answer: (d) None of these

The question asks for a non-linear structure, where one element can be connected to several others (trees and graphs). Every structure offered here is linear:

a string is a sequence of characters stored one after another (a character array);
a list keeps its elements in a single sequence, each with at most one next element;
a stack is a linear LIFO sequence where insertion and deletion happen at the top.

Since none of them is non-linear, the answer is "None of these".

Why the other options are wrong

(a) Strings: linear; characters follow one another in a single sequence.
(b) Lists: linear; each element has one predecessor and one successor (except the ends).
(c) Stacks: linear; a stack is a restricted list that adds and removes only at one end.

Tip: If no tree or graph appears among the options, "None" is the answer to "which is non-linear?".

Source: Lecture Plan: Data Structures (CSC 13102), IIT (ISM) Dhanbad

Question 19Networking

Which is the standard protocol for network management features?

a)FTP
b)SNA
c)SNMP
d)SMTP

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Question 20Networking

How many pairs of stations can simultaneously communicate on an Ethernet LAN?

a)1
b)2
c)3
d)Multiple

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Question 21Networking

A path for carrying signals between a source and a destination is known as-

a)Router
b)Channel
c)Link
d)Block

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Question 22Database

In SQL, the ________ command is used to recompile a view.

a)COMPILE VIEW
b)DEFINE VIEW
c)ALTER VIEW
d)CREATE VIEW

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Question 23Operating Systems

Which of the following process scheduling algorithm may lead to starvation?

a)FIFO
b)Round Robin
c)Shortest Job Next (correct answer)
d)None of these

Answer and explanation

Correct answer: (c) Shortest Job Next

Shortest Job Next (another name for Shortest Job First) always runs the waiting job with the shortest CPU burst; it is priority scheduling with priority = 1 / next CPU burst, so long jobs get the lowest priority. If short jobs keep arriving, a long job is passed over again and again and may never get the CPU. This indefinite postponement is starvation. The usual cure is aging: raising a job's priority the longer it waits.

Why the other options are wrong

(a) FIFO: the same as FCFS; jobs are served strictly in arrival order, so each one is reached after the finite number of jobs ahead of it. Waits may be long, but there is no starvation.
(b) Round Robin: every ready process gets a time quantum in turn, so with n ready processes and quantum q nobody waits more than (n − 1) × q for the next turn. No starvation.
(d) None of these: wrong because SJN can starve long jobs.

Tip: Starvation-prone: SJF/SJN, SRTF, Priority. Starvation-free: FCFS/FIFO, Round Robin.

Source: Chapter 2: Process Scheduling (EE442 Operating Systems, METU)

Question 24Software Engineering

Which of the following requires the most time in SDLC?

a)Requirement Analysis
b)Testing
c)Deployment
d)Design

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Question 25Networking

POP3 is a protocol for-

a)Email Sending
b)Email Composing
c)Email Receiving (correct answer)
d)Email Storing

Answer and explanation

Correct answer: (c) Email Receiving

POP3 (Post Office Protocol version 3) lets a mail client (for example on a PC or phone) connect to the mail server, usually on TCP port 110 (995 for POP3 over TLS), log in, and download the messages the server is holding in its mailbox (maildrop). By default the messages are then deleted from the server, so mail is read offline on the device. It is therefore a protocol for retrieving, i.e. receiving, e-mail.

Why the other options are wrong

(a) Email Sending: Sending and relaying mail is done by SMTP; RFC 1939 explicitly leaves out how a client enters mail into the transport system.
(b) Email Composing: Writing a message is done locally in the mail client (user agent); no network protocol is involved until the message is sent.
(d) Email Storing: Mailbox storage is the mail server's job. POP3 only gives access to the stored maildrop and is not meant for extensive manipulation of mail on the server; that is IMAP's role.

Tip: SMTP pushes mail out; POP3 and IMAP pull mail in (POP3 downloads, IMAP keeps it synced on the server).

Source: RFC 1939: Post Office Protocol - Version 3

Question 26Programming

Which of the declarations is correct?

a)int length; (correct answer)
b)char int
c)int long;
d)float double;

Answer and explanation

Correct answer: (a) int length;

A C declaration has the form: type specifier(s), then at least one declarator (the variable name), then ;. int length; gives the type int and the identifier length, and length is not a keyword, so it compiles cleanly.

Why the other options are wrong

(b) char int: char and int are two different base types and cannot be combined; gcc reports "two or more data types in declaration specifiers". There is also no variable name.
(c) int long: long int (in any order) is a valid type, but nothing is declared. The C rules forbid an empty declarator here; gcc warns "useless type name in empty declaration" and g++ gives the error "declaration does not declare anything".
(d) float double: float and double are two base types; gcc reports "two or more data types in declaration specifiers", and no variable is named.

Tip: A declaration needs a type and a name that is not a keyword: type name;.

Source: Declarations - cppreference.com

Question 27Networking

Which server can you use to dynamically assign IP addresses to the PCs in a LAN?

a)DHCP Server
b)Web Server
c)DNS Server
d)FTP Server

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Question 28Programming

Which of the following is the destructor of class Vehicle?

a)*Vehicle()
b)~Vehicle ()
c)~Vehicle (int value)
d)*Vehicle (int value)

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Question 29Mathematics

An n*n array v is defined as follows: v [i, j]=i-j for all i, j; 1<=i<=n, 1<=j<=n, the sum of the element of array v is

a)0
b)n-1
c)n²-3n+2
d)n²(n+1)/2

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Question 30Algorithms

What is the time complexity of Huffman coding?

a)O(n)
b)O(n log n) (correct answer)
c)O(n (log n)^2)
d)O(n^2)

Answer and explanation

Correct answer: (b) O(n log n)

Huffman coding keeps the trees in a min-priority queue (binary min-heap) keyed by frequency. With n symbols:

Build the heap of n single-node trees: O(n).
Repeat n − 1 times: extract-min twice, join the two trees, insert the new tree. Each heap operation costs O(log n).
Total: O(n) + (n − 1) × 3 × O(log n) = O(n log n).

Example: 6 symbols with frequencies 5, 9, 12, 13, 16, 45 → 5 merges (5 + 9 = 14, 12 + 13 = 25, 14 + 16 = 30, 25 + 30 = 55, 45 + 55 = 100), i.e. 10 extract-min and 5 insert operations.

Why the other options are wrong

(a) O(n): possible only when the frequencies arrive already sorted (then two plain FIFO queues replace the heap, because merged weights are produced in non-decreasing order); the standard algorithm on arbitrary input is not linear.
(c) O(n (log n)^2): an overestimate; each of the n − 1 steps costs O(log n), not O((log n)²).
(d) O(n^2): what you get if you find the two minima by scanning an unsorted list each time (n − 1 scans of O(n)); a heap avoids this.

Exam note: n is the number of distinct symbols and the standard heap-based algorithm is assumed.

Tip: Huffman = greedy + min-heap → O(n log n).

Source: Huffman coding — Dictionary of Algorithms and Data Structures (NIST)
Source: Greedy Algorithms, lecture slides, A. Carzaniga, Università della Svizzera italiana

Question 31Programming

The operator that cannot be overloaded is ______.

a)++
b)()
c)~
d)::

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Question 32Data Structures

The maximum number of binary trees that can be formed with three unlabeled nodes is-

a)1
b)3
c)5
d)4

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Question 33Networking

Which of the following TCP/IP addresses constitute the loopback address?

a)1.1.1.1
b)255.255.255.255
c)127.0.0.0
d)127.0.0.1

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Question 34Programming

Find the output of the following Java code line: System.out.println(Math.floor(-7.4))

a)-7
b)-7.4
c)-8
d)-7.2

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Question 35Programming

Which of the following functions converts a string into float in Python?

a)int(x [, base])
b)float(x)
c)long(x [, base])
d)str(x)

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Question 36Programming

What is the output of the following code? print 9//2

a)4
b)4.0
c)4.5
d)Error

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Question 37Programming

Which function overloads the ">>" operator?

a)gt()
b)more()
c)ge()
d)None of these

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Question 38Programming

Which of the following operator functions cannot be global, i.e., must be a member function?

a)Conversion operator
b)new
c)delete
d)all of these

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Question 39Programming

Which of the following is not an operator in Java?

a)instanceof
b)sizeof
c)new
d)All of these

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Question 40Programming

Which of these is not a core data type?

a)Lists
b)Dictionary
c)Class
d)Tuples

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