GE 2115 FOC 2 MARKS WITH ANSWER
TWO MARKS
UNIT
I
1.WHAT
IS COMPUTER ?
Computer is a data
processing device which automatically accepts and stores input data, processes
them and produces results under the direction of a detailed step by step
program.
2.Characteristics
of a computers :
Ø Speed
Ø Accuracy
Ø Automatic
Ø Endurance
Ø Versatility
Ø Storage
Ø Reduction
in cost
Ø No
Intelligent Quotient
Ø Resource
Sharing
3.Five generations of computers:
1. First Generation (1940-56)-Vacuum
Tubes.
2. Second Generation
(1956-63)-Transistors.
3. Third Generation (1964- Early
1970’s) -Integrated Circuits.
4. Fourth Generation (Early
1970’s-Till date) -Microprocessors.
5. Fifth Generation (Present
and Beyond) -Artificial Intelligence.
4.Advantages of First Generation computer:
1. Vacuum tubes were only
electronic components available at that time.
2. These computers were the
fastest calculating device of their time.
3. These computers could
perform calculations in milliseconds.
5.Disadvantages of First Generation computer:
1. Very big in size.
2. Occupies large space.
3. High heat production.
4. High power consumption.
5. High cost.
6.Advantages of Second Generation computer:
1. Small in size.
2. Better reliability.
3. Computational time is
Micro Seconds.
4. Less heat generated.
5. Better speed.
7.Disadvantages of Second Generation
computer:
1. Frequent Maintenance
required.
2. Need Air conditioning.
3. Manual Assembly of
individual components into a functioning unit was required.
4. High cost.
5. Commercial production was
difficult.
8.Advantages of Third Generation computer:
1. Small in size.
2. More reliability.
3. Less heat is generated.
4. Computational time is
nanoseconds.
5. Less hardware failure.
6. Low Maintenance cost.
7. Easily portable.
8. General purpose computers.
9. Less power required.
10. Commercial production was
easier and cheaper.
9.Disadvantages of Third Generation computer:
1. Need Air conditioning.
2. Highly sophisticated
Technology required for the manufacture of IC chips
10.Advantages of Fourth Generation computer:
1. Small in size.
2. Very cheap.
3. More reliability.
4. Less Hardware failures.
5. Large and Faster primary
and secondary storage.
6. Object oriented languages
are supported.
11.Disadvantages
of
Fourth Generation computer:
1. Highly sophisticated
Technology is required for the manufacture of LSI chips.
12.Advantages of Fifth Generation
computer:
1. Consumes less power.
2. User Friendly.
3. Supports parallel
programming.
4. Supports wide operating
system environment.
5. Having much faster and
large primary storage capacity.
13.Types of computer based on
Hardware Design:
Based on hardware Design computers
are classified as follows
v Analog
v Digital
v Hybrid
14.Types of computer based on Utility:
Based on utility, the
computers can be classified into
a)
General purpose computer
b)
Special purpose computer
15.Types of computer based on size
and capacity:
Based on size and capacity, computers
are classified into the following
a)
Micro computer
b)
Mini computer
c)
Mainframe computer
d)
Super computer
16.Types of computer based on Mode of
Use:
Based on Mode of Use, computers are
classified into the following
a) Palmtop PCs
b) Laptop PCs
c) Personal computer
d) Work station
e) Mainframe system
f) Clients
and Server
17.Analog Devices:
In Analog computer, the input data is
continuously changing electrical or non electrical information. Computations
are carried out with physical quantities such as Voltage, Length, Current;
Temperature etc. The devices measuring such quantities are called Analog
Devices.
18.Analog Signals:
An Analog Signal is a continuous
variable electromagnetic wave and it consumes an infinite number of voltage or
current values.
19.Difference between Analog and
Digital computer:
Analog
computers
|
Digital
computers
|
It operates by measuring
|
It
operates by counting
|
It requires physical analog
|
It functions on discrete numbers
|
The calculations are first converted to equation and later converted
to equation and later converted into electrical signals.
|
The calculations are converted into binary numbers(1’s and 0’s)
|
The output in the form of graph.
|
The output in the form of discrete values.
|
Less accurate
|
More accurate.
|
Less speed
|
High Speed
|
Limited memory
|
More memory
|
Lack of flexibility
|
Highly flexible
|
20.Three units of the block diagram
of the computer:
·
Input unit
·
Central Processing unit
·
Output unit
21.Uses of
Input unit
Ø Send information or
instructions or commands to the computer.
Ø Data received from the
input unit is immediately stored in main memory and then processed.
22.Uses of Output
unit
·
Output Unit is the communication between the user and the
computer.
·
Devices used to get the response or result of a process from
the computer is called output.
·
The output Unit of a computer provides the information and
results of a computation to the outside world.
UNIT
II
1.
How
did the internet works?
a. Fig:
Internet Connection Sharing
2.
What
is network ARPANET?
The network had to connect four computers
running on four different operating systems. They are called network ARPANET.
3. What is web page?
A
web page or webpage is a document or resource of information that is
suitable for the World Wide Web and can be accessed through a web browser and displayed on a computer screen.
4. What
is Website?
A website (or web site) is a collection of
related web pages, images, videos or other digital assets that are addressed
with a common domain name or IP address in an Internet Protocol-based network.
5. Define
Homepage
?
Ø
The homepage (often written as
home page) is the URL or local
file that automatically loads when a web
browser starts or when the browser's "home"
button is pressed. You can turn this feature off and on, as well as specify a
URL for the page to be loaded.
Ø The term
is also used to refer to the front
page, web server directory index, or main
web page of a
website of a group, company, organization, or individual.
6.
Define
Web
browser ?
Ø
A web browser is a software
application for retrieving, presenting, and traversing information resources on
the World Wide Web.
Ø
An information resource is
identified by a Uniform Resource Identifier (URI) and may be a web page, image,
video, or other piece of content.
Ø Hyperlinks
present in resources enable users to easily navigate their browsers to related
resources
7.
What is start page?
Ø A start page is a website or page meant to
organize links or information for the user when a web
browser starts. Start pages generally consist of
information like news, weather, games, and other web widgets and web gadgets.
8.
What
is URL?
Ø
Uniform Resource Locator, the
global address of documents and other resources on the World Wide Web.
Ø
The first part of the address
is called a protocol identifier and it indicates what protocol to use and the
second part is called a resource name and it specifies the IP address or the
domain name where the resource is located. The protocol identifier and the
resource name are separated by a colon and two forward slashes.
Ø
For example, the two URLs
below point to two different files at the domain pcwebopedia.com.
9.
What is ISP ?
Ø
Internet Service Provider, a
company that provides access to the Internet. For a monthly fee, the service
provider gives you a software package, username, password and access phone
number. Equipped with a modem, you can then log on to the Internet and browse
the World Wide Web and USENET, and send and receive e-mail.
Ø
In addition to serving
individuals, ISPs also serve large companies, providing a direct connection
from the company's networks to the Internet. ISPs themselves are connected to
one another through Network Access Points (NAPs).
Ø
ISPs are also called IAPs
(Internet Access Providers).
10.
Define
HTTP
?
Ø HTTP stands for Hyper Text Transfer
Protocol.
Ø It is the primary protocol of the World
Wide Web (WWW).
Ø HTTP has an ability to transfer Web pages,
graphics and any other type of media that is used on the Web in Hyper Text
Markup Language (HTML), the internal format of Web pages.
11.
Draw
a hierarchy of Internet:
12. Define Webserver:
Ø A computer that delivers (serves up) Web
pages. Every Web server has an IP address and possibly a domain name.
o For example, if you enter the URL
http://www.pcwebopedia.com/index.html in your browser, this sends a request to
the server whose domain name is pcwebopedia.com. The server then fetches the
page named index.html and sends it to your browser.
Ø There are many Web server software
applications, including public domain software from NCSA and Apache, and
commercial packages from Microsoft, Netscape and others.
13. Define Download:
Ø To copy data (usually an entire file) from
a main source to a peripheral device.
Ø The term is often used to describe the
process of copying a file from an online service or bulletin board service
(BBS) to one's own computer.
Ø Downloading can also refer to copying a
file from a network file server to a computer on the network.
14. Define Upload:
Ø The opposite of download is upload, which
means to copy a file from your own computer to another computer.
Ø To transmit data from a computer to a
bulletin board service, mainframe, or network.
Ø For
example, if you use a personal computer to log on to a network and you want to
send files across the network, you must upload the files from your PC to the
network.
15. What is the use of router?
A router is useful in the following
ways.
·
It
ensures that information doesn’t go where it’s not needed. This is crucial for
keeping large volumes of data from clogging the connections of “innocent
bystanders”.
·
It
makes sure that information does not make it to the indented destination.
16. Define Routers:
Ø The
routers determine where to send information from one computer to another.
Ø Routers
are specialized computers that send your messages and those of every other
internet user speeding to their destinations along thousands of path ways.
17.
Define Backbones:
Ø Backbones
are typically fiber optic trunk lines.
Ø The
trunk lines has multiple fiber optic cables combined together to increase the
capability.
Ø Today
there are many companies that operate their own high capacity backbones and all
of them are interconnected at various NAPs around the world.
18.
Define World Wide Web (www):
Ø The
world web wide is the name given to
the entire part of the internet.
Ø The
World Wide Web consists of millions of web
sites (google, yahoo…) and web pages.
Ø Web
page is a kind of word processing document except it can contain pictures, sounds,
movies along with the text.
Ø Anyone
who knows HTML can make a web page.
19.
Define Electronic mail or
e-mail or mail:
Ø Electronic mail
is one of the most popular uses of internet.
Ø If
you have an e-mail account you can send an electronic message to anyone by
knowing their e-mail address.
Ø If
you have an internet service provider (ISP) or commercial online service that
you already have and know your e-mail address. Example Rajaas4u@redifmail.com
20.
Define Chat:
Ø Online
conversations in which you are immediately able to send the messages back and
forth to one another are called chat.
Ø Here
chatting can be done without using the telephone.
Ø Online
chat doesn’t cost anything extra, as long as you have an internet connection.
21.
Define Remote Access:
Ø The
internet allows computer users to connect to other computer.
Ø This
is encouraging new days of working from home, collaboration and information
sharing in many countries.
Ø For
example an accountant sitting at the home can audit the books on a server
suited in another country that maintained remotely by IT specialist in a forth.
22.
Define File Transfer Protocol
(FTP):
Ø FTP
is a network protocol which is used to transfer data from one computer to
another through a network.
Ø Transfer Protocol
(TP) is a file transfer protocol for exchanging the files over any TCP/IP based
network.
Ø There
are many FTP client and server Programs.FTP servers can be set up anywhere
between game servers, voice servers, internet host, and other physical servers.
23.
Define Voice Telephony (VoIP):
Ø VoIP
stands for Voice over IP (Internet Protocol) that underlies all internet
communications.
Ø This
phenomenon began as an optimal two way extension to some of instant messaging
systems.
Ø The
benefit is that, as the internet carries the actual voice traffic, VoIP can be
free of cost much less than a normal telephone call.
Ø Currently
few of the VoIP’s provides an emergency services but it is not universally available.
24.
Define Telnet
(Telecommunication Network):
Ø Telnet
is a network protocol used on the internet or local area network (LAN) connections.
Ø The
term telnet also refers to software which implements the client part of the
protocol.
Ø TELNET
clients have been available on most UNIX systems for many years.
Ø Most
network equipment and OSs with a TCP/IP stack support some kind of TELNET
service server for their remote configuration.
25. Define Internet
Protocol: IP address
Ø Every
machine on the internet has a unique identify number, called an IP address.
Ø The
IP address stands for Internet Protocol, which is the language that computers
use to communicate over the internet.
Ø A
protocol is a predefined way that someone who wants to use a service talks with
the service.
Ø A
typical IP address look like this:
10.10.0.255
27. Hardware
Hardware represents physical
components of the computer. The hardware performs all operation in the computer
such as accepting and sorting data, performing calculations and displaying or printing
etc.
Some of the physical devices are
Monitor, Floppy disk drive, Hard disk drive, Keyboard, Printer etc.
28.Software
The set of instruction
grouped into programs that make the computer to function in the desired way. It
is a collection of programs, to perform a particular task.
29.
DIFFERENCE BETWEEN SOFTWARE AND HARDWARE
SL.NO
|
SOFTWARE
|
HARDWARE
|
1.
|
It is
the collection of program to bring the computer hardware system into
operation.
|
It is
the physical components of the computer system.
|
2.
|
It consists
of numbers, alphabets, alphanumeric, symbols, identifiers, keywords etc.
|
It
consists of electronic components like IC’s, diodes, resistors, crystals,
boards, insulators etc.
|
3.
|
This
should be prepared according to the type of the computer.
|
The design
can be modified according to the category.
|
4.
|
It
will vary as per the computer and its built-in function and programming
language.
|
It is
almost construct for all types of computer system.
|
30. TYPES OF SOFTWARE
The
Software is widely available and it may be vast and variety of software’s is
there Software’s are categorized into the following.
Fig:
Types of Software
31.
System Software
·
A
System Software is a collection of programs designed to operate, control and
extended processing capabilities of computer and which makes the operation of a
computer system more efficiently
32.
Functions of Operating System
The below abstraction layer shows a
collection of interacting hardware and software elements, functioning at
different levels
33.Software Piracy
Software piracy is the unauthorized copying of an organization
internally developed software or the illegal duplication of commercially
available software.
34.Types of Software Piracy
There
are six basic forms of software piracy.
1.
Soft
loading
2.
Software
Counterfeiting
3.
Renting
4.
Hard
Disk Loading
5.
License
Misuse
UNIT III:
1.Application
software:
Application
software is a set of program that are used to perform some specific task, such
as word processing, drawing figures, maintaining database etc.
2.commonly used office packages
1.
Word Processing.
2.
Spread sheet.
3.
Graphics Packages.
4.
Personal Assistance
Packages.
3.Features of Word Processor:
The following are the main features
of a Word Processor
1. Fast
2. Editing
Features
3. Permanent
Storage.
4. Formatting
Features.
5. Graphics.
6. OLE(Object
Linking and Embedding)
7. Spell
check.
8. Tables.
9. Revise
without Retyping.
10. Mail
Merge.
4.Options provided by MS-Word are
1. Entering
and Editing Text.
2. Viewing
Documents.
3. Formatting
Text.
4. Formatting
Documents.
5. Tables.
6. Graphics.
7. Mail
Merge and Labelling.
8. Printing.
5. Spread sheet:
·
An Electronic Spread
sheet or a Spread sheet is a table of rows and columns into which data is
entered
·
Spread sheet software
makes it possible to enter data into a task format, manipulate, store, print
and create reports and graphics using them.
6.Parts of Spread sheet:
·
Columns.
·
Rows.
·
Cells.
·
Cell Pointer.
7. Features of Spread sheet:
1. Complicated
calculation can be performed easily.
2. The
result of the calculation is accurate.
3. The
Worksheet can be edited.
4. Data
can be viewed as graph.
5. The
information stored in a work sheet can be transferred to other software
programs.
8.Graphics Packages:
Graphics package is a collection
program which enables us to create, edit, View, Store, Retrieve and Print,
Drawings, Pictures, Graphs and anything that can be drawn using computer
system.
9.Features of Graphics Packages:
1. Draw
Designs.
2. Computer
Aided Design / Drafting(CAD/ CADD)
3. Paint
Drawing and Pictures.
4. Present
Graphs.
5. Graphics
in Medical Technology
6. Presentation Graphics.
10.Application of Computer Graphics Packages:
Some
of the application of Computer Graphics Packages are
·
Computer Aided Design /
Drafting(CAD/CADD)
·
Desktop Publishing.
·
Computer Art.
·
Graphical User
Interface(GUI)
·
Computer Aided
Learning(CAL)
·
Geographical
Information System(GI)
·
Internet.
11.Personal Assistance Package:
·
Personal assistance package is
to use personal computers for storing and retrieving their personal
information, planning, managing their schedules, contacts, finances etc. It
commonly supports business people to know the current status of the company.
12.Features of Personal Assistance Package:
Some of the commonly used activities for
the business persons are
1. Personal
Information.
2. Address
Book.
3. Investment
Book.
4. Inventory
Book.
5. Purchase
order.
6. Purchase
return.
7. Sales.
8. Sales
return.
9. Remuneration.
13.Personal Assistance Package:
Personal assistance package is
to use personal computers for storing and retrieving their personal
information, planning, managing their schedules, contacts, finances etc. It
commonly supports business people to know the current status of the company.
14.Pseudo code
Pseudo
code is a format design tool. Developed
with the structured programming .It is a visual, narrative and more easily used
for structured design. It is a programming analysis tool.
“Pseudo” means initiation or false,
”Code” means the set of statements or instructions written in a programming language. Pseudo
code is also called “Program Design
Language (PDL)”.
15.Rules
for writing Pseudo code
The following rules used for writing pseudo
code
·
Write one statement per
line.
·
Capitalize initial
keywords.
·
Indent to show
hierarchy.
·
End multiline
structure.
·
Keep statements
language independent.
16.Advantages and Disadvantages of Pseudo code
Advantages
a) It
can be done easily in any word processor.
b) It
can be easily modified as compared to flowchart.
c) Its
implementation is very useful in structured design elements.
d) It can be written easily.
e) It
can be read and understood easily.
f) Converting
a pseudo code to programming language is very easy as compared with converting
a flowchart to programming language.
Disadvantages
a) It
is not visual
b) We
do not get a picture of the design.
c) There
is no standardized style or format, so one pseudo code may different from
another.
d) For
a Beginner, it is more difficult to follow the logic or write pseudo code as
compared to flowchart.
17.Sequence logic:
The sequence logic is
used for performing instructions one after another. Thus the pseudo code
instruction of sequence logic are written in an order in which they are to be
performed. The logic flow of pseudo code is top to bottom approach.
18.Selection logic:
The selection logic is used
for decisions and also known as decision logic. It is used for selecting the
suitable ports out of the two or more parts in logic of the program. It is
usually depicted as an IF….THEN or IF…..THEN….ELSE or a CASE structures.
19.Iteration logic(looping)
This logic is used for
producing loops in program logic, when one or more instructions may be executed
several times or depending on some condition. It uses two structures called the
WHILE and the DO…WHILE, both of these structures are used for looping. The
looping continues until the condition becomes true.
20.Algorithm
Algorithm is defined as a sequence of executable instructions that forms
a solution to a particular problem. It is also defined as a procedural solution
to solve a problem.
21.CHARACTERISTICS OF ALGORITHMS:
1)
Algorithm’s each and every instructions
should be precise.
2)
Algorithm’s each and every instructions
should be unambiguous.
3)
Instructions should not be repeated
infinitely.
4)
Algorithm should terminate ultimately.
5)
Algorithm should be in sequence.
6)
V should look like normal English.
7)
The desired output should be obtained
only after the algorithm terminates.
22.REPRESENTATION OF ALGORITHM
Algorithm is represented in following ways.
1)
Normal English
2)
Flowchart
3)
Pseudo code
4)
Decision table
5)
Program
23.FLOWCHARTS
Ø A
flowchart is a diagrammatic representation that illustrates the sequence of
operation to be performed to arrive the desired solution.
Ø It
is a pictorial representation of an algorithm.
24.NEED FOR FLOWCHARTS:
Ø Flowchart
has a standardized meaning, that makes
the program logic easy.
Ø It
is easy to read and interrupt.
25.ADVANTAGES OF FLOWCHART:
Ø
Better communication.
Ø
Effective analysis.
Ø
Effective synthesis.
Ø
Effective coding.
Ø
Proper program documentation.
Ø
Systematic debugging.
Ø
Systematic testing.
UNIT IV
1.Data
Data refers to a collection of facts, or numbers or symbols.
2.Data
types
Data type is a term that refers to the kind of data in a
program
C++ data types can be classified as
·
Basic (primitive) data types [ int, char,
float, double]
·
User defined data types
·
Derived data types
3.User
defined data types
User defined data types are data types defined by the
user
Ø
Enumeration (enum)
Ø
Typedefinition (typedef)
Ø
Structure (struct)
Ø
Union (union)
Ø
Class
(class)
4.Variable
Variable is the address of a
data that associates the reserved memory for data storage in the main memory
(RAM) with a symbolic name.
Reference variable
Reference
variable is a variable which provides an
alternative name for a previously defined variable.
Syntax
datatype &reference name = variable name
Example float a = 10;
float &b = a;
Here a is a variable and b is a reference variable.
5.Modifiers
(Qualifiers)
Modifiers (Qualifiers) are
keywords that are prefixed with the basic data types and produce new extended data
type.
Example:
unsigned, signed, short, long.
6.Operator
Operator is a symbol that is used to manipulate (operate) the data
7.Operand
The data items that the operators can
act upon are called operands i.e. Data is otherwise called operand
8.Unary and Binary operator
The
operator that uses a single operand is called a unary operator
Example: a++
here
++ is an unary operator
The operator that uses two operands
is called binary operator
Example: a+b
here + is the binary
operator
9.Operators in C
·
The arithmetic operators
Binary Arithmetic
|
Unary Arithmetic
|
||||
Operators
|
Operation
|
Operators
|
Operation
|
||
+
|
Addition
|
+
|
Unary
plus
|
||
-
|
subtraction
|
-
|
Unary
minus
|
||
*
|
multiplication
|
++
|
Increment
|
||
/
|
division
|
--
|
decrement
|
||
%
|
remainder
|
||||
10.The
equality and relational operators
Relational operator
|
Meaning
|
Equality Operator
|
Meaning
|
>
|
Greater
than
|
==
|
Equal
to
|
>=
|
Greater
than or equal to
|
||
<
|
Less
then
|
!=
|
Not
equal to
|
<=
|
Less
then or equal to
|
11.The
logical operators
Binary logical operator
|
Operation
|
&&
|
Logical AND (AND gate operator)
|
||
|
Logical OR(OR gate operator)
|
Unary logical operator
|
operation
|
!
|
Logical NOT (NOT gate operator)
|
·
The simple assignment operator =
·
The compound assignment operators
Operator
|
Usage
|
effect
|
+=
-=
*=
/=
%=
&=
|=
^=
<<=
>>=
|
a+=exp;
a-= exp;
a*= exp;
a/= exp;
a%= exp;
a&= exp;
a|= exp;
a^= exp;
a<<= exp;
a>>= exp;
|
a=a+(exp);
a=a-(exp);
a=a*(exp);
a=a/(exp);
a=a%(exp);
a=a&(exp);
a=a|(exp);
a=a^(exp);
a=a<<(exp);
a=a>>(exp);
|
12.The
increment and decrement operators
++, - -
13.Conditional operator(Ternary Operator)
An
alternative method to using a simple if-else construct is the conditional
expression operator ?:
Syntax
expression1
?expression2 : expression3
|
14.Bitwise
and bit shift operators
15.Expression
Any valid combination of constants
or operators or operands or variables is called an expression, A constant or a
variable alone may allow be treated as an expression
Example a+b-c
16.Statement
An expression followed by a semicolon (;) is called
statement
Example a+b-c;
17. Unformatted I/O
statements
v This
statements are used to I/O a single/group of characters from/ to the I/O
devices.
v The
user cannot specify the type of the data that is going to be I/O.
18.
putchar() function
·
The putchar() function
is used to display one character at a time on the standard output device.
·
This function does the
reverse operation of the single character input function as discussed above.
Syntax:
|
putchar(character variable);
|
Eg:
|
Char x; //declaration statement
putchar(); //output statement
|
19.
getc() function
This is used to accept a single
character from the standard input to a character variable.
|
char
variable=getc ();
|
|
Char x; //declaration statement
X=getc(); //input statement
|
20.putc()
function
This is used to display a single
character from the character variable to a standard output device.
|
putc(character variable);
|
Eg:
|
Char x; //declaration statement
putc(); //output statement
|
21.gets()
function
This is used to read the string
(string is a group of character) from the standard input device(keyboard).
|
gets(char type of array variable);
|
22.puts()
function
This is used to display/write
string to a standard output device.
Syntax:
|
puts(char type of array variable);
|
23.Scanf()
function
Input data can be entered into the
computer using the standard input ‘C’ library function called scanf(). This
function is used to enter any combination of input.
Syntax:
|
Scanf(“control
string”,&var1,&var2,….&varn);
|
24. Rules for writing scanf () function:
a. The
control string must be preceded with & sign and must be within quotations.
b. If
there are a number of input data items, that items must be separated by commas
& must be preceeded with & sign except for string input.
c. The
control string & the variables going to input should match with each other.
d. It
must have termination with the semicolon.
25. Rules for writing printf () function:
a. Place
appropriate headings in the output.
b. If
there are a number of input data items, that items must be separated by commas
& must be preceeded with & sign except for string input.
c. The
control string and the variables must match in their order.
d. The
control string must be within quotations and there we can also use any other
text to print with data.
e. Provide
blank space in between the members.
f. Print
special message, whenever occurs in output.
26. Branching statement:
Branching statement alter sequential execution of
program statement. The following are the branching statements
Ø If statement
Ø If-else statement
Ø Switch statement
Ø Goto statement
27. If statement
o
If statement is a conditional
statement it is used to execute or skip one statement or group of statementsfor
a particular condition.
o Syntax:
if(test-condition)
{
Statement block;
}
next statement;
28. if-else statement:
o
if-else statement is a
conditional statement ,tit is used to execute one group of statements if the
test-condition is true or other group if the test-conditon is false .
o
Syntax:
if(test-condition)
{
Statementblock1;
}
else
{
Statementblock2;
}
Next statement;
29. Switch statement
o
Switch statement is a
conditional statement . It is an extension of if-else statement this permits
any number of branches.
o
Syntax;
Switch(expression)
{
Case label 1:
Statement
block1;
Break;
Case label 2:
Statement
block1;
Break;
……………………………..
…………………………….
Case label n:
Statement
block1;
Break;
}next statement;
30. Goto statement :
o
Goto is an unconditional branching
statement. Goto statement is used to transfer the program control
unconditionally from one point to another .
o
Syntax:
goto Label;
label is the name given to the point where the control has to be
transferred
UNIT V
1.Function
Function is a module (sub program)
which performs a particular task (job/action). A large program is divided into
a number of small programs called subprogram or module.
2.Parameter passing
- Parameter passing is a
mechanism for communication of data between the calling function(caller)
and the called function(callee)
- A function that
invokes(calls) another function is known as a calling function (caller)
- A function which is
invoked (called) by another function is known as a called function(callee)
3.Methods (ways) of calling a function or
parameter passing methods
1. Call by
Reference or pass by reference
2. Call by
Address or pass by address
3. Call by
Value or pass by value
4.Call by Value
Call by
value is a parameter passing method or method of calling a function by passing the value of an argument
(parameter) to the function
- When an argument is
passed call by value ,a copy of the arguments value is made and passed to
the called function
- Change to the parameter
within the function will effect only the copy(formal parameter) and will
have no effect on the actual parameter.
5.Call
by Address
Call by Address is a parameter
passing method or method of calling a function by passing the address of an
argument to the function
- When the argument is passed the address of
the argument is copied instead of value
- Changes to the parameter within the
function will affect both the formal and actual parameter.
6.Call
by Reference
Call by
reference value is a parameter passing method or method of calling a function
which has the syntax of call by value and the functionality of call by address
Any modification made through the
formal parameter is also reflected in the actual parameter.
7.Strings
In “C” language the group of
character,digits,and symbols enclosed within quotation marks are called as
string otherwise strings are array of characters.Null character (‘\0’)is used
to mark the end of the string.
Example :
Char
name [ ] = {‘B’,’A’,’U’,’\0’}
Each character is stored in one byte of
memory and successive characters of the string are stored in successive byte.
8.
The strlen() function
This
function is used to count and return the number of characters present in a
string.
Syntax
|
Var=strlen(string);
|
Description
|
Var Is the integer variable which
accepts . the length of the string
String Is the string constant or string
variable,in which the length
is going
to be found.the counting
ends with
first null character
|
9.
The strcpy() function
This
function is used to copy the contents of one string to another string,it almost
works like string assignment operator.
Syntax
|
Strcpy(string1,string2);
|
Description
|
String1 is the destination operator.
String2 is the source operator.
|
i.e.The
contents of string2 is assigned to the contents of string1.
10.
The strcmp() function
This
is a function which compares two strings to find ou whether they are same or
not.The two strings are compared character by character till the end of the
string.If the two strings are identical strcmp() returns zero,else it returns a
numeric difference between the first non matching characters.
Syntax
|
Strcat(string1,string2);
|
Description
|
String1
and string2 are character type arrays or string constants.
|
11.
The Strrev() function
The strrev() function is
used to reverse a string.This function takes only one argument and return one
argument.The general form of strrev() function is
Syntax
|
Strrev(string1);
|
Description
|
String1
is character type arrays or string constants.
|
12.Structure
:
A
structure is a user defined data type used to represent different types of data
with a single name. The data items in a structure are called members of a
structure.
Syntax:
Struct
tag-field
{
datatype
member1;
datatype
member2;
…..
…..
datatype
member n;
}
13.Union:
Union is like a structure data type in which
all the members share the same memory area.
Syntax;
Union
tag-field
{
datatype member1;
datatype member2;
……
……
datatype membern;
}variable1 ,variable2,…variable n;
14.Uses
of Union:
Union needs less
memory space than structure. Union can be used to store temporary variables of
different data types i.e., They are useful for applications involving number of
variables , where values need not be assigned to all elements at one time.
15.Difference
between Union and structure
·
A union can provide storage for one member at a
given time. But a structure can provide storage for all members.
·
The amount of space allocation for union is
based upon the member which requires the largest memory space. But in structure
each member is given memory space .
·
In Union at one time we can refer any one
variable.but in structure we can refer all the variables.
16.Array:
Array is the derived datatype that
contains multiple values, sequence of finite data items of the same data type
that share a common name.
17.Pointer:
Pointer is the derived data types
that contains the address of the variable.
18.What is preprocessor:
Preprocessor is a program that
process our source program before compilation.
Ø These
are placed before the main()
function in the source program.
Ø The
compiles examines the preprocessor for any preprocessor directives.
If there is any
preprocessor directives, the appropriate action are taken and then the source
program is moved for compilation
19.Preprocessor directives:
|
a) File inclusion.
b) Macro substitution.
c)
Conditional inclusion.
|
20.
File inclusion:
Ø This
is used to include an external file, which contains functions or some other
macro definitions to our source program.
|
#include”file
name” and
#include<filename>
|
Example:
|
#include<stdio.h>
#include’loop.c”
|
21.
Macro Substitutions:
Ø This
is used to define symbolic constants in
the source program.
Ø The
identifier or string define is replaced by macro substation.
|
#define
identifier string/integer
|
22.Types
of Macros:
v Simple macros
v Argumented macros
v Nested macros
23.
Simple macros
Ø
This is commonly used to define
symbolic constants
|
#define age 20
#define CITY “CHENNAI”
#define g 9.8
#define A 10
|
Ø
The #define A 10 macro substitutes ‘A’
with 10 in all occurrence in the
source program.
24.
Argumented macros
Ø
The argumented macros are used to
define more complex form of replacement in the source program.
|
#define identifier (v1 v2 v5….v4) string/integer
|
25.Nested macros
Ø
The macros define in another macro
called nested macros.
|
#define A
5
#define B A+2
|
26. Rules
for defining preprocessor:
a)
Every processor must start with
# symbol.
b)
The processor is always placed
before main() function.
c)
The preprocessor cannot have
termination with semicolon
d)
There is no argument operator
in #define statement.
e)
The conditional macro must be
terminated (#ifdef, #endif)
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