COMPUTER APPLICATION BASIC QUESTIONS

1 What is C language?

C is a middle level programming language. C is a Structured, procedural

programming language. It is widely used both for operating systems and

Applications.

2 What is an argument? Differentiate between formal arguments and

actual arguments?

Using argument we can pass the data from calling function to the called function.

Arguments available in the function definition are called formal arguments. Can be

preceded by their own data types.

We use Actual arguments in the function call.

3 What is the purpose of main ( ) function?

Main function is to be called when the program is getting started.

1. It is the first started function.

2. Returns integer value.

3. Recursive call is allowed for main () also.

4. It is user-defined function

5. It has two arguments:

5.1) argument count

5.2) argument vector (strings passed)

6. We can use any user defined name as parameters for main (), behalf of argc and

argv.

4 What is a pointer variable?

A pointer variable is used to contain the address of another variable in the memory.

5 What is static memory allocation and dynamic memory allocation?

Information regarding static memory allocation and dynamic memory allocation are

given below:

Static memory allocation:

The compiler allocates the required memory space for a declared variable. Using the

address of operator, the reserved address is obtained and assigned to a pointer

variable. Most of the declared variables have static memory; this way is called as

static memory allocation. In the memory is assign during compile time.

Dynamic memory allocation:

For getting memory dynamically It uses functions such as malloc ( ) or calloc ( ).the

values returned by these functions are assigned to pointer variables, this way is

called as dynamic memory allocation. In this memory is assigned during run time.

6 What is difference between static and global static variable?

Main difference between static and global static variables is given below:

In context of memory it allocated to static variables only once.

Static global variable has scope only in the file in which they are declared. outside

the file it can not be accessed. but its value remains intact if code is running in some

other file

7 What is a function and built-in function?

function is that when large program is divided into sub programs. where as each one

done one or more actions to be performed for a large program. Those subprograms

are called functions. they support only static and extern storage classes.

Built-in functions (Library function) that which are predefined and supplied with the

compiler called as built-in functions.

8 Difference between arrays and pointers?

Arrays automatically allocate space with fixed in size and location, but in pointers

above are dynamic.

array is referred directly to the elements.

but a pointer refers to address of the elements.

9 what are storage variable?

A storage class changes the behavior of a variable. It use to controls the lifetime,

scope and linkage.

There are five types of storage classes:

1. auto

2. static

3. extern

4. register

5. typedef

10 what are header files? Can we run program without using header file?

Basically header files are the library functions. Header files have definitions of

functions. These are required to execute the specific operation of function. we write

header file with .h extension. Generally these are pre-defined fuctions, But we can

also generate our own header file.

Example:

stdio.h header file is use to perform function like prinf and scanf.

conio.h header file is use to perform function like clrscr and getch.

11 What is macro?

Macros are the fragment of code. That is used to given a name. When we want to

used threw name it is being replaced by content of macros. we can differentiate

macros in terms of what they look like & when they are used. Macros are of two

types:

1. Object-like macros.

2. Function-like macros.

When we used Object-like macros It resembles data objects. Where as when we

using function-like macros it resembles function calls

12 What are the three OOPS principles and define them?

Encapsulation, Inheritance and Polymorphism are the three OOPs

Principles.

Encapsulation:

Is the Mechanism that binds together code and the data it manipulates, and keeps

both safe from outside interference and misuse.

Inheritance:

Is the process by which one object acquires the properties of another object.

Polymorphism:

Is a feature that allows one interface to be used for a general class of actions.

13 What is the use of bin and lib in JDK?

Bin contains all tools such as javac, applet viewer, awt tool etc., whereas Lib

contains all packages and variables.

14 What are the kinds of variables in Java? What are their uses?

Java has three kinds of variables namely, the instance variable, the local variable and

the class variable. Local variables are used inside blocks as counters or in methods

as temporary variables and are used to store information needed by a single method.

Instance variables are used to define attributes or the state of a particular object and

are used to store information needed by multiple methods in the objects.

Class variables are global to a class and to all the instances of the class and are

useful for communicating between different objects of all the same class or keeping

track of global states.

15 What is the difference between while statement and a do statement?

A while statement checks at the beginning of a loop to see whether the next loop

iteration should occur. A do statement checks at the end of a loop to see whether the

next iteration of a loop should occur. The do statement will always execute the body

of a loop at least once.

16 Which method is used to determine the class of an object?

get Class ( ) method can be used to find out what class the belongs to. This class is

defined in the object class and is available to all objects.

17 Which keyword is used to create an instance of a class?

new.

18 Which method is used to garbage collect an object?

finalize ().

19 What are packages? what is use of packages?

The package statement defines a name space in which classes are stored. If you omit

the package, the classes are put into the default package.

Signature... package pkg;

Use: * It specifies to which package the classes defined in a file belongs to. * Package

is both naming and a visibility control mechanism

20 What do you understand by package access specifier?

public: Anything declared as public can be accessed from anywhere

private: Anything declared in the private can’t be seen outside of its class.

default: It is visible to subclasses as well as to other classes in the same package.

21What is difference between interface and an abstract class?

All the methods declared inside an Interface are abstract. Where as abstract class

must have at least one abstract method and others may be concrete or abstract.

In Interface we need not use the keyword abstract for the methods

22 What is the difference between ‘throw’ and ‘throws’? And it’s

application?

Exceptions that are thrown by java runtime systems can be handled by Try and

catch blocks. With throw exception we can handle the exceptions thrown by the

program itself. If a method is capable of causing an exception that it does not

handle, it must specify this behavior so the callers of the method can guard

against that exception

23 When can subclasses not access super class members?

When super class is declared as private.

24Which class does begin Java class hierarchy?

Object class

25 What are the three types of modeling in UML?

Structural, behavioral, and architectural.

26 What is OOPS Architecture?

Takes care structural and behavioral aspect of a software system.

Includes software usage, functionality, performance, reuse, economic and technology

constraints.

27 What are Messages?

Specification of a communication.

28What is component diagrams?

A component diagram is particularly useful with teams of larger size.........

29What are the various components in sequence diagrams?

Actor: Actor represents an external user / end user who interact with the system.

30What are the parts of a deployment diagram?

Nodes: A node represents any hardware component. The configuration of hardware is

represented by attributes of nodes..........

31. What is database?

A database is a logically coherent collection of data with some inherent meaning,

representing some aspect of real world and which is designed, built and populated

with data for a specific purpose.

32. What is DBMS?

It is a collection of programs that enables user to create and maintain a database. In

other words it is general-purpose software that provides the users with the processes

of defining, constructing and manipulating the database for various applications.

33. Define the "integrity rules"?

There are two Integrity rules.

1. Entity Integrity: States that "Primary key cannot have NULL value"

2. Referential Integrity: States that "Foreign Key can be either a NULL value

or should be Primary Key value of other relation.

34. What is view?

A view may be thought of as a virtual table, that is, a table that does not really exist

in its own right but is instead derived from one or more underlying base table. In

other words, there is no stored file that direct represents the view instead a definition

of view is stored in data dictionary.

35. What is E-R model?

This data model is based on real world that consists of basic objects called entities

and of relationship among these objects. Entities are described in a database by a set

of attributes.

36. What is DDL (Data Definition Language)?

A data base schema is specifies by a set of definitions expressed by a special

language called DDL.

37. What is DML (Data Manipulation Language)?

This language that enable user to access or manipulate data as organized by

appropriate data model.

1. Procedural DML or Low level: DML requires a user to specify what data are

needed and how to get those data.

2. Non-Procedural DML or High level: DML requires a user to specify what

data are needed without specifying how to get those data.

38. What is normalization?

It is a process of analyzing the given relation schemas based on their Functional

Dependencies (FDs) and primary key to achieve the properties

(1).Minimizing redundancy, (2). Minimizing insertion, deletion and update anomalies.

39. What is BCNF (Boyce-Codd Normal Form)?

A relation schema R is in BCNF if it is in 3NF and satisfies an additional constraint that

for every FD X A, X must be a candidate key.

40. What do you mean by atomicity and aggregation?

1. Atomicity: Either all actions are carried out or none are. Users should not

have to worry about the effect of incomplete transactions. DBMS ensures this

by undoing the actions of incomplete transactions.

2. Aggregation: A concept which is used to model a relationship between a

collection of entities and relationships. It is used when we need to express a

relationship among relationships.

41.What is data structure?

A data structure is a way of organizing data that considers not only the items stored,

but also their relationship to each other. Advance knowledge about the relationship

between data items allows designing of efficient algorithms for the manipulation of

data.

42. What is the data structures used to perform recursion?

Stack. Because of its LIFO (Last In First Out) property it remembers its 'caller' so

knows whom to return when the function has to return. Recursion makes use of

system stack for storing the return addresses of the function calls.

Every recursive function has its equivalent iterative (non-recursive) function. Even

when such equivalent iterative procedures are written, explicit stack is to be used.

43. Sorting is not possible by using which of the following methods?

(Insertion, Selection, Exchange, Deletion)

Sorting is not possible in Deletion. Using insertion we can perform insertion sort,

using selection we can perform selection sort, using exchange we can perform the

bubble sort (and other similar sorting methods). But no sorting method can be done

just using deletion.

44. In an AVL tree, at what condition the balancing is to be done?

If the 'pivotal value' (or the 'Height factor') is greater than 1 or less than -1.

45. In tree construction which is the suitable efficient data structure?

(Array, Linked list, Stack, Queue)

Linked list is the suitable efficient data structure.

46. What is the type of the algorithm used in solving the 8 Queens

problem?

Backtracking

47. What is a spanning Tree?

A spanning tree is a tree associated with a network. All the nodes of the graph

appear on the tree once. A minimum spanning tree is a spanning tree organized so

that the total edge weight between nodes is minimized.

48. Whether Linked List is linear or Non-linear data structure?

According to Access strategies Linked list is a linear one.

According to Storage Linked List is a Non-linear one.

49. Which is the simplest file structure? (Sequential, Indexed, Random)

Sequential is the simplest file structure.

50. What are the types of Collision Resolution Techniques and the methods

used in each of the type?

1. Open addressing (closed hashing), The methods used include: Overflow

block.

2. Closed addressing (open hashing), The methods used include: Linked list,

Binary tree.

51. Explain Belady’s anomaly?

Also called FIFO anomaly. Usually, on increasing the number of frames

allocated to a process virtual memory, the process execution is faster,

because fewer page faults occur. Sometimes, the reverse happens, i.e., the

execution time increases even when more frames are allocated to the

process. This is Belady's Anomaly. This is true for certain page reference

patterns.

52 hat is a binary semaphore? What is its use?

A binary semaphore is one, which takes only 0 and 1 as values. They are used

to implement mutual exclusion and synchronize concurrent processes.

53 hat is thrashing?

It is a phenomenon in virtual memory schemes when the processor spends

most of its time swapping pages, rather than executing instructions. This is

due to an inordinate number of page faults.

54 List the Coffman's conditions that lead to a deadlock.

a. Mutual Exclusion: one process may use a critical resource at a time.

b. Hold and wait: A process may be allocated some resources while

waiting for others.

c. No pre-emption: No resource can be forcible removed from a process

holding it.

d. Circular wait: A closed chain of processes exists such that each process

holds at least one resource needed by another process in the chain.

55 What is short, long and medium-term scheduling?

Long term scheduler determines which programs are admitted to the

system for processing. It controls the degree of multiprogramming. Once

admitted, a job becomes a process.

Medium term scheduling is part of the swapping function. This relates to

processes that are in a blocked or suspended state. They are swapped out of

real-memory until they are ready to execute. The swapping-in decision is

based on memory-management criteria.

Short term scheduler, also know as a dispatcher executes most frequently,

and makes the finest-grained decision of which process should execute next.

This scheduler is invoked whenever an event occurs. It may lead to

interruption of one process by preemption.

56 What are turnaround time and response time?

Turnaround time is the interval between the submission of a job and its

completion. Response time is the interval between submission of a request,

and the first response to that request.

57 When is a system in safe state?

The set of dispatchable processes is in a safe state if there exists at least one

temporal order in which all processes can be run to completion without

resulting in a deadlock.

58 What is cycle stealing?

We encounter cycle stealing in the context of Direct Memory Access (DMA).

Either the DMA controller can use the data bus when the CPU does not need

it, or it may force the CPU to temporarily suspend operation. The latter

technique is called cycle stealing. Note that cycle stealing can be done only at

specific break points in an instruction cycle.

59 What is a trap and trapdoor?

Trapdoor is a secret undocumented entry point into a program used to grant

access without normal methods of access authentication. A trap is a software

interrupt, usually the result of an error condition.

60 Define latency, transfer and seek time with respect to disk I/O.

Seek time is the time required to move the disk arm to the required track.

Rotational delay or latency is the time it takes for the beginning of the

required sector to reach the head. Sum of seek time (if any) and latency is the

access time. Time taken to actually transfer a span of data is transfer time.

61.Define Network?

A network is a set of devices connected by physical media links. A network is

recursively is a connection of two or more nodes by a physical link or two or

more networks connected by one or more nodes.

62. Define Routing?

The process of determining systematically hoe to forward messages toward

the destination nodes based on its address is called routing.

63 Define Bandwidth and Latency?

Network performance is measured in Bandwidth (throughput) and Latency

(Delay). Bandwidth of a network is given by the number of bits that can be

transmitted over the network in a certain period of time. Latency corresponds

to how long it t5akes a message to travel from one end off a network to the

other. It is strictly measured in terms of time.

64 what is protocol?

A protocol is a set of rules that govern all aspects of information

communication.

65 When a switch is said to be congested?

It is possible that a switch receives packets faster than the shared link can

accommodate and stores in its memory, for an extended period of time, then

the switch will eventually run out of buffer space, and some packets will have

to be dropped and in this state is said to congested state.

66 Define the terms Uncasting, Multicasting and Broadcasting?

If the message is sent from a source to a single destination node, it is called

Unicasting.

If the message is sent to some subset of other nodes, it is called Multicasting.

If the message is sent to all the m nodes in the network it is called

Broadcasting.

67 What is multiplexing?

Multiplexing is the set of techniques that allows the simultaneous

transmission of multiple signals across a single data link.

68 Which layers are network support layers?

a.Physical layer

b.Data link layer

c.Network layer

69 What is Error Detection? What are its methods?

Data can be corrupted during transmission. For reliable communication errors

must be deducted and Corrected. Error Detection uses the concept of

redundancy, which means adding extra bits for detecting errors at the

destination.

70 Define Encoder?

A device or program that uses predefined algorithms to encode, or compress

audio or video data for storage or transmission use. A circuit that is used to

convert between digital video and analog video.

71.What is Polymorphism?

Polymorphism is phenomena by which we can make make a method for reuse.

Polymorphism is an object oriented term. Polymorphism may be defined as the

ability of related objects to respond to the same message with different, but

appropriate actions. In other words, polymorphism means taking more than one

form. Polymorphism leads to two important aspects in Object Oriented terminology -

First one is function Overloading and second is function Overriding. Overloading is

the practice of supplying more than one definition for a given function name in the

same scope. The compiler is left to pick the appropriate version of the function or

operator based on the arguments with which it is called. Overriding refers to the

modifications made in the sub class to the inherited methods from the base class to

change their behavior

72 What is the difference between "overloading" and "overriding"?

Differences are there-

Overloading a method (or function) in C++ is the ability for functions of the same

name to be defined as long as these methods have different signatures (different set

of parameters). Method overriding is the ability of the inherited class rewriting the

virtual method of the base class.

overriding is runtime polymorphism while overloading is compile time polymorphism.

73 What is the advantage of function overloading according to users point

of view?

We know that function name is same. But each time we are writing code for each

function. In this case it is advantageous than normal function.

74 What is Operator overloading?

When an operator is overloaded, it takes on an additional meaning relative to a

certain class. But it can still retain all of its old meanings.

Examples:

1) The operators >> and << may be used for I/O operations because in the header,

they are overloaded.

2) In a stack class it is possible to overload the + operator so that it appends the

contents of one stack to the contents of another. But the + operator still retains its

original meaning relative to other types of data.

75 What is the difference between an object and a class?

Class and Objects are diff but related concepts. Every objects belongs to the class

and very class has a one or more related objects.

Classes are:

> A Class is static.

> A class combination of data(called data members)and functions(called member

functions).

> Class is a user defined data type with data members and member functions.

> Classes defines object.

> One class can define any no of Object.

> Class is a template(type) or blue print its state how objects should be and behave.

Objects are:

> Object is an instance of a class while a class can have many objects.

> Object is a dynamic.

> Objects are the basic runtime entities in an object oriented system.

> Data and function which combine into a single entity is called object.

> Objects are instances of classes which identifies the class properties.

> Object can't define classes.

> Object can created and destroyed as your necessity.

> Object is defined as a s/w construct which binds data and logic or

methods(functions) both.

76 What are the advantages of inheritance?

It permits code reusability. Reusability saves time in program development. It

encourages the reuse of proven and debugged high-quality software, thus reducing

problem after a system becomes functional.

77Explain the scope resolution operator.

It permits a program to reference an identifier in the global scope that has been

hidden by another identifier with the same name in the local scope.

78 What are Identifiers

A valid identifier is a sequence of one or more letters, digits or underscores

characters (_). Neither spaces nor punctuation marks or symbols can be part of an

identifier. Only letters, digits and single underscore characters are valid. In addition,

variable identifiers always have to begin with a letter. They can also begin with an

underline character (_ ), but in some cases these may be reserved for compiler

specific keywords or external identifiers, as well as identifiers containing two

successive underscore characters anywhere. In no case they can begin with a digit

79 what is the difference between parameter and argument?

Diff b/w parameter and argument is :

Argument basically is one of the following -

> An Expression in the comma-separated list in a function call.

> A sequence of one or more preprocessor tokens in the comma-separated list in a

macro call.

> Its represent the value which you pass to a procedure parameter when you call the

procedure. The calling code supplies the arguments when it calls the procedure.

> It is something passed into a function(value), whereas a parameter is the type of

data plus the name.

Parameter basically is one of the following -

> An object that is declared in a function declaration or definition.

> An identifier b/w the parentheses immediately following the macro name in a

macro definition.

> It is represent a value that the procedure expects you to pass when you call it. The

procedure's declaration defines its parameters.

This example explains the difference b/w a parameter and an argument:

80)What is the difference between class and structure?

Diff b/w Class and Structure is :

Class is defined as-

>Class is a successor of Structure. By default all the members inside the class are

private.

>Class is the advanced and the secured form of structure.

>Classes are reference typed.

>Class can be inherited.

>In Class we can initials the variable during the declaration.

>Class can not be declared without a tag at the first time.

>Class support polymorphism.

Structures define as :

> In C++ extended the structure to contain functions also. All declarations inside a

structure are by default public.

> Structures contain only data while class binds both data and member functions.

> Structure doesn’t support the polymorphism, inheritance and initialization.

> Structure is a collection of the different data type.

> Structure is overloaded.

> Structures are value type.

> Structure can be declared without a tag at the first time

81What is .NET?

.NET is essentially a framework for software development. It is similar in nature to

any other software development framework (J2EE etc) in that it provides a set of

runtime containers/capabilities, and a rich set of pre-built functionality in the form of

class libraries and APIs

The .NET Framework is an environment for building, deploying, and running Web

Services and other applications. It consists of three main parts: the Common

Language Runtime, the Framework classes, and ASP.NET.

82 How many languages .NET is supporting now?

When .NET was introduced it came with several languages. VB.NET, C#, COBOL and

Perl, etc. The site DotNetLanguages.Net says 44 languages are supported

83 How is .NET able to support multiple languages?

A language should comply with the Common Language Runtime standard to become

a .NET language. In .NET, code is compiled to Microsoft Intermediate Language (MSIL

for short). This is called as Managed Code. This Managed code is run in .NET

environment. So after compilation to this IL the language is not a barrier. A code can

call or use a function written in another language.

84 How ASP .NET different from ASP?

Scripting is separated from the HTML, Code is compiled as a DLL, and these DLLs can

be executed on the server.

85 What is smart navigation?

The cursor position is maintained when the page gets refreshed due to the server

side validation and the page gets refreshed.

86 What is view state?

The web is stateless. But in ASP.NET, the state of a page is maintained in the in the

page itself automatically. How? The values are encrypted and saved in hidden

controls. this is done automatically by the ASP.NET. This can be switched off / on for a

single control

87 How do you validate the controls in an ASP .NET page?

Using special validation controls that are meant for this. We have Range Validator,

Email Validator.

88 Can the validation be done in the server side? Or this can be done only

in the Client side?

Client side is done by default. Server side validation is also possible. We can switch

off the client side and server side can be done.

89 How to manage pagination in a page?

Using pagination option in Data Grid control. We have to set the number of records

for a page, then it takes care of pagination by itself.

90 What is ADO .NET and what is difference between ADO and ADO.NET?

ADO.NET is stateless mechanism. I can treat the ADO.Net as a separate in-memory

database where in I can use relationships between the tables and select insert and

updates to the database. I can update the actual database as a batch.

91 What is computer architecture?

It is the art of assembling logical elements into a computing device; the specification

of the relation between parts of a computer system.

92 What are the basic functional units of a computer?

Input, memory, arithmetic and logic unit, output and control units are the basic

functional units of a computer

93 Define Response time and Throughput.

Response time is the time between the start and the completion of the event. Also

referred to as execution time or latency. Throughput is the total amount of work done

in a given amount of time.

94 What is the function of memory unit? how will you classify it?

  The function of the memory unit is to store programs and data, there are two

classes of storage, called primary and secondary.

 95 Explain the concept behind pipelining.

Pipelining is an implementation technique whereby multiple instructions

are overlapped in execution. It takes advantage of parallelism that exists among

actions needed to execute an instruction.

96 What are timing signals?

Timing signals are signals that determine when a given action is to take place. the

actual timing signals that govern the transfers are generated by control circuits.

97 Which memory is non-volatile and may be written only once?

PROM

98 What is flip flop?

A flip flop is 1 bit memory.

99 What is addressing modes?

Each instruction of a computer specifies an operation on certain data. The are various

ways of specifying address of the data to be operated on. These different ways of

specifying data are called the addressing modes

100. What is the time complexity of Merge Sort?

O (long)