CP Notes

WWW.VIDYARTHIPLUS.COM

WWW.VIDYARTHIPLUS.COM ENGG

GE6151-Computer Programming

Sem/Year: I/I Regulation: 2013

Unit-1

Generations of Computer:

It means step by step growth in the technology.

Each phase of computer has been extended to include both hardware and software, together make up

an entire computer system.

Based on the period of development, the features and technological advancement, the computer has

been classified into various generations.

There are five generations of computer:

1. First generation

2. Second generation

3. Third generation

4. Fourth generation

5. Fifth generation

1. First generation:

The late forties and the early fifties have seen computer hardware using “vacuum tubes”.

The concept of stored program was introduced by “von newmann”.

Vacuum tube circuitry as such these were quite large.

Vacuum tube was one of the high speed electronic devices and could perform computations in

milliseconds.

In this generation used the “machine language binary language.(0’s &1’s)

No operating system used.

MEMORY: 10000 to 20000 characters.

Advantages:

1) Vacuum tubes were the only electronic components.

2) The fastest calculating device.

3) It performs computations in milliseconds.

4) It first digital computers.

Disadvantages:

1. very big in size

2. high heat production

3. high power consumption

4. no reliability

5. need constant maintenance

2. Second generation:

”John Bardeen” invented a new electronic device called “transistor”.

It is very small in size &less expensive &produces less heat.

The storage capacity: up to 64000 characters.

They used “Assembly level” programming language.

Memory: magnetic core & magnetic disk.

Batch operating systems ruled the second generation compute in micro seconds.

Advantages:

1) Small in size

2) Better reliability

3) Computational time is micro seconds

4) Less heat generated

5) Better speed & portability

Disadvantages:

1) Need air-conditioning

2) High cost

3) Frequent maintenance required

3. Third generation:

These generations were introduced in the mid sixties.

these were based on “Integrated circuits(IC)”

The IC chips were made of silicon.

MEMORY:”semi conductor memory”.



Programming language “high level language” used

Memory capacity: up to “4 million characters”.

It performs computations in “nano seconds”.

FORTRAN, BASIC, PASCAL, COBOL languages are used.

Advantages:

1) Small in size

2) More reliability

3) Less heat generated

4) Computational time in nano seconds.

5) Low maintenance cost

Disadvantages:

1. need air-conditioning

2. special technology for manufacture of IC chips

Example: IBM, CDC, PDP, ICL, Honeywell.

4. Fourth generation:

Development of the microprocessor in 1972.

when integrated with storage, input & output units, a microprocessors produces a micro

computer

They are interactive & respond directly * immediately to the user’s input.

the languages used: 4th generation language

MEMORY: “semi conductor memory(no range)

Processing speed: 1 to 10 nano seconds.

Advantages:

1) Small in size

2) Very cheap

3) Consumed less power

4) Having more reliability

5) Object oriented languages are supported

Disadvantages:

1) Special technology required for manufacture of LSI chips.

Example: INTEL, APPLE, IBM

5. Fifth generation:

Computers are machines that perform only when instructed.

They may operate at fast speed & perform with unbelievable accuracy.

But they are unable to act (or) think on their own.

artificial intelligence machine could be developed which will be think & decide

MEMORY: “magnetic bubble memories”(CMOS).

Speed: 1 to 100 nano seconds.

Languages: artificial intelligence

Advantages:

1) More user friendly

2) Support parallel programming & user friendly environment.

3) This generation is super computers.

4) It supports power applications.

Characteristics of computer:

o The computer is an intelligent machine that solves problems and performed much faster,

accurately and efficiently.

o The characteristics of computers are listed below:

1. Speed

2. Accuracy

3. Automatic

4. Endurance

5. Versatility

6. Storage

7. Reduction in cost

8. No intelligent quotient

1. Speed:

o Speed is the most important characteristic of a computer.



o It can perform in few seconds, the amount of work that a human being can do in an entire

year.

Example:

10 digit numbers multiply with 5 digit number human take hours and hours. But computer

take only few nano seconds.

2. Accuracy:

o The computers are perfect, accurate and precise(correct)

o Accuracy signifies (mention) the reliability of the hardware components of a computer.

Example:

Only an accurate computer can guide a rocket to reach the space in the pre determined path.

3. Automatic:

o The computers are works automatically.

o Once programs are stored & data given to it, then every instruction automatically transferred one

by one for execution.

o The CPU follows these instructions until it meets the last instruction execution.

4. Endurance:

o The computer can go on working continuously and does not suffer tiredness and lack of

concentration.

Example:

If three million calculations given to computer, three millionth calculate give the same

accuracy and same speed of first calculation.

5. Versatility:

o The computer can be put to various jobs and has applications in various fields.

Example: Weather forecasting, teaching, railways, medicine, industry and banking, etc.,

6. Storage:

o The computer processes limitless quantities of data and information.

o Various memories such as primary, secondary.

Example: Random Access Memory (RAM), Hard Disk Drive (HDD), Floppy, Magnetic tapes.

7. Reduction in cost:

o Initial investment cost may be high, but reduces the cost of each transaction and cost of

computers.

o It reduces man power and space requirements and greater efficiency.

8. No intelligent quotient:

o The computer carryout task much faster than human being.

o But computer cannot think its own.

Classification of computers:

Computes are available in different shape, size &weights.

The computers are classified as following:

Based on Hardware Design Analog

Digital

Hybrid

Based on Utility General Purpose Computer

Special Purpose Computer

Based on Size & Capacity Micro Computers

Mini Computers

Main Frame Computers

Super Computer

Based on Mode of use Palmtop

laptop

Personal Computer

Work Station

Main Frame System

Clients & Server

BASED ON HARDWARE DESIGN:

Based on Hardware Design Computers are classified as

(a)Analog Computer



(b)Digital Computer

(c)Hybrid Computer

(a)Analog Computer

The Analog computer operate by “Measuring” instead of “Counting”

Computers are carried out with physical qualities such as voltage, length, current, Temperature.

Analog Computer, the input data is Continuously Changing electrical (or) non-electrical

information.

Example: Electronic weighing scale, patient heart beat, blood pressure, temperature.

(b)Digital Computer

Digital computer with quintiles represented as digits

It both numeric & non-numeric information is representation as strings of digits.

It represented by binary numbers 0’s &1’s.

A digital signal consists of discrete voltage level represent binary 1 (ON) (or) binary 0(OFF)

It is much faster than Analog Computers

Example: Business, Scientific Applications

(c)Hybrid Computer

Hybrid Computers, made combine the qualities of both analog & Digital Computers.

Measuring functions are performed by the analog way.

Logic functions are designed in nature

Example: Personal Computer

Analog Digital

1)It operates by measuring

2)the calculations are converted to equation &

converted into electrical signals

3)Less accurate

4)lass Speed

5)Limited Memory

6)Lack of Flexible

7)Limited Applications

1)It operates by Counting

2)the calculations are converted into Binary

values(0’s&1’s)

3)More accurate

4)High Speed

5)More Memory

6)Highly Flexible

7)Many number of Applications

BASED ON UTILITY:

Based on utility the computers can be classified into

(a)General Purpose Computer

(b)Special Purpose Computer

(a)General Purpose Computer

These are designed & constructed to satisfy almost all the need of the society.

They are able to perform according to the program created to meet different needs.

These can used for Varity of tasks financial accounting, Designing textile prints and etc.

They are also flexible & can be used to work on business & scientific problems.

(b)Special Purpose Computer

Special Purpose Computer can be designed to perform specific functions.

In such devices, the instructions are permanently pre programmed in internal memory.

Some of Special Purpose Computers are aircraft control system, electronic voting machines &

Computer in hospital, etc.

BASED ON SIZE & CAPACITY:

Based on size & capacity, Computers are classified into the following:

(a) Micro Computer

(b) Mini Computer

(c) Main frame Computer

(d) Super Computer

(a)Micro Computer

Micro computers are small in size use of microprocessor

A microprocessor is a processor whose components of input, output & CPU are in single IC chip

These are used in office, homes, schools, shops, stores, .etc.

(b) Mini Computer

Mini computers larger than micro computers &more powerful in terms of processing speed

It mainly multiprocessor systems where many operations can perform simultaneously.

It has greater storage capacity & larger memories as compared to micro computer



These are handling more Input & Output devices.

c) Mainframe computer:

Mainframe computer are larger, faster &more expensive than other computers.

These are used to handle huge volumes of data.

These computers work with more than one processor at same time.

These are multiuser, multi processor system.

These are used to solve the very complex calculations.

It is used in large industries, government organizations, banks, airline reservations. Where large

database is required.

d) Super computer:

Super computer is the most powerful of all computers.

They are high speed.

They are mainly used for purposes handle very large amount of data & to be processed within a

very short time.

It is used in weather forecasting, space research, weapons research, atomic research, design of

aircrafts, etc….

BASED ON MODE OF USE:

Based on made of use can be classified into

A. Palmtop,

B. Laptop,

C. Personal computer,

D. Work station,

E. Clients & server.

a) Palmtop:

Palmtop is accepting hand written inputs using an electronic pen.

These have small disk storage &connected to a wireless network.

A palmtop computer has also facilities to be used as phone &tablets.

b) Laptop computer: Laptops are portable computer with less weight & small in size to rest on the lap.

Laptops are attached with keyboard, mouse, monitor & CPU in single booklet.

It will run in batteries & connected to a network.

It used for miniature components which consume low power.

c) Personal computer:

The personal computer is name itself implies the use of personal things.

It mainly designed to meet personal computing requirements of users at working place (or) at home.

It is non-portable & general purpose computer. This can easily fit in on office table.

It is rapidly changed the work culture &individuals.

The pc used by children & all the peoples & everywhere.

It is usually designed two models:

i) Desktop model--------- bed type CPU

ii) Tower model-------------stand type CPU.

d) Workstation:

It is a powerful desktop computer designed to meet computing needs of users or clients.

It has better processing, high storage &effective graphics display.

It is similar to pc can be used through “local area network” (LAN).

e) Clients & server:

With the increased gain of computer networks, it is possible to interconnect several computers.

It is very useful to share resources & services among the multiple users.

There are two varieties of system used.

Server:

It is a large computer that manages a shared resources &services to the clients.

Clients:

It is single pc & supports a user friendly interface with end user.

It sends the request to the server &accesses the resources in server.

BASIC ORGANIZATION OF COMPUTER



The architecture of the computer has not changed, but the technology may be vary from one computer

to another computer.

However, the basic organization of computers remains the same for all computers.

The basic computer architecture shown in the figure.

The computers have the following three units:

1. Input unit

2. Central processing unit

3. Output unit

1. INPUT UNIT:

o Computer must need the data and instructions in order to solve any problem.

o Therefore we need to give data and instruction through the input unit.

o The input unit consists of one or more input devices.

Input Device Functions:

i. Accept data and instruction from the outside word.

ii. Convert it to a form that the computer can understand.

iii. Supply the converted data to the computer.

Following are some of the input devices:

Keyboard, mouse, light pen, joystick, Optical Character Recognizer (OCR), Optical Mark Recognizer

(OMR), Track ball, etc.,

2. CENTRAL PROCESSING UNIT:

o It is the heart and brain of the computer.

o Because of all operations are carried out in CPU only.

o CPU doing the following operations :

(i) All calculations and all decisions.

(ii) Controls and co-ordinates all units

(iii) Interprets (converts) instructions of program.

(iv) Stores data temporarily and monitors the external request.

CPU is sub divided into following:

(i) Control unit

(ii) Arithmetic & logic unit

(iii) Memory unit

a) Primary storage

b) Secondary storage

i) Control unit:

o The control unit instructs the computer how to carry out program instruction.

o It drives the flow of data between memory and arithmetic and logic unit

o It controls and co-ordinates the all other units.

Central Processing Unit (CPU)

Control Unit

Memory Unit

Secondary storage

Arithmetic and

Logic Unit

Input Unit Output Unit

Control Flow

Data Flow



o The input unit does not know when receive data & where to put the data.

o It drives & instruct the receiving it.

o It controls the flow of data & instruction from & to of

(i) Storage, ALU

(ii) ALU, storage.

o The control unit also controls what should be sent to the output unit.

o During program execution, control unit fetches instruction from primary memory, decodes them

to determine which operation required.

ii) Arithmetic & logic unit:

Arithmetic& logic unit performs all the arithmetic &logical operations.

Arithmetic operations like additions, subtractions, multiplications, divisions.

Logical operations like AND, OR, NOT for comparisons.

ALU also does comparisons &takes decision; the control unit transfers the required data from storage

unit to ALU.

Calculations finished data transferred to storage unit.

iii) Memory unit:

o Memory is the part of computer holds data for processing.

o Memory is divided into two categories:

a) Primary memory

b) Secondary memory

o A memory that stores program instructions (or) data used by CPU for performing any operations.

o Memory is device which store information temporarily (or) permanently.

a) Primary memory:

o The primary memory also called as “main memory”.

o It hold the program being currently executed in the computer,

o This primary memory is temporarily store the data for processing by CPU.

o The RAM (Random Access Memory) used as primary memory.

o Each &ever information can process through any main memory.

o It is fast & expensive.

o Computer speed also include with this memory.

RAM ROM

Random Access Memory or RAM is a form of data

storage that can be accessed randomly at any time, in

any order and from any physical location. Allowing

quick access and manipulation.

Read-only memory or ROM is also a form of data

storage that cannot be easily altered or

reprogrammed.

Random Access Memory Read-only memory RAM allows the computer to read data quickly to run

applications. It allows reading and writing. ROM stores the program required to initially boot

the computer. It only allows reading. RAM is volatile i.e. its contents are lost when the

device is powered off. It is non-volatile i.e. its contents are retained even

when the device is powered off. The two main types of RAM are static RAM and

dynamic RAM. The types of ROM include PROM, EPROM and

EEPROM.

b) Secondary storage:

The secondary storage is also known as auxiliary storage.

It is used like an archive (secure) & permanent storage.

It may store several programs, documents, database, etc.

After running the program, we need to save the results and program, transfer them to secondary

storage.

Secondary memory is slower, cheaper than the primary memory

It holds the larger amount of data &b it is also call non-volatile memory.

Some devices are floppy, hard disk drive, CD-ROM (Compact Disc), Pen drive, etc.

3. Output Unit

Devices used to get the response or result of process from the computer is called output

The output unit of computer provides the information and the result of computation to the outside

world



Computer can understand only binary system, so that output device convert into human understand

format

Output devices: Monitor, Printer, Plotter, and Speaker etc.

Number System

Introduction:

A number is required for counting or express the amount of some quantity.

It consists of group of symbols called digits, which are arranged in definite manner.

There are many ways to digits are arranged to form a number.

various ways of representing number system:

1. Decimal number system(0,1,2,......9)

2. Octal number system(0,1,2,.....7)

3. Hexadecimal number system(0,1,2,........9,A,B,C,D,E,F)

4. Binary number system(0&1)

The number of digits in system is called radix or base.

The number systems are basically two types:

a. Non positional number system.

b. Positional number system.

a. Non positional number system:

o This method of counting uses non positional number system or additive approach

o Using this system, the symbols are

o I for 1 II for 2 III for 3 IIII for 4 etc...,

Disadvantage:

o It is difficult to perform arithmetic operations.

b. Positional Number System:

o It is uses few symbols called digits.

o Such symbols specify different values depending on the position.

Example: 7734.25(10)

o The base or radix is the total number of digits available in the number system

1. Decimal Number System:

o This system is base 10 or radix 10 number system.

o There contain all 10 numbers.

o 0,1,2,3,4,5,6,7,8,9.

o In this representation has two types of digits

1) Most significant digit (MSD)

2) Least significant digit (LSD)

o Base of this number system may be represented or not

Example:

7293.25

5 x 10-2 5 x 1

100 0.05

2 x 10-1 2 x 1

10 0.20

3 x 100 3 x 1 3.00

9 x 101 9 x 10 90.00

2 x 102 2 x 100 200.00

7 x 103 7 x 1000 7000.00

7293.25

2. Binary Number System:

o In a binary system have only two digits 0&1

o This system is called radix 2 or base 2 systems.

o The computer can works with only binary system

o Because digital pulse represents 1 for high voltage (5v) 0 for low voltage (0v)

o Binary representation:

Position 5 4 3 2 1 -1 -2 -3 -4



Weights 24 23 22 21 20 2-1 2-2 2-3 2-4

Values 16 8 4 2 1 0.5 0.25 0.125 0.0625

Binary representation of some numbers

Decimal Octal Hexadecimal Binary

0 0 0 0000

1 1 1 0001

2 2 2 0010

3 3 3 0011

4 4 4 0100

5 5 5 0101

6 6 6 0110

7 7 7 0111

8 8 1000

9 9 1001

10 A 1010

11 B 1011

12 C 1100

13 D 1101

14 E 1110

15 F 1111

3) Octal Number System:

The number system with base 8 or radix 8 is has only 8 digits 0,1,2,3,4,5,6,7.

Position 5 4 3 2 1 -1 -2 -3

Weights 84 83 82 81 80 8-1 8-2 8-3

Values 4096 512 64 8 1 0.125 0.0156 0.00195

Example:

Conversion of Octal to Binary

(25)8

(25)8 = (010101)2

Conversion of Octal to decimal

(25)8

(25)8 = (21)10

Conversion of Octal to Hexadecimal

(25)8

1. Convert octal to binary

2. Convert Binary to Hexadecimal

(25)8 = (15)16

Need for logical analysis & thinking:

Logical thinking is the process of understanding something logically.

Only through logical thinking we can achieve the specific goals & targets.

Logic is the basic form of the concept, judgment and reasoning.

When finalizing the goal or target of something, we have put together our judgment & reasoning to

reflecting reality.

2 5

010 101

5 x 80 5 x 1 5

2 x 81 2 x 8 16

21

2 5

010 101

0001 0101

1 5



PROBLEM SOLVING:

Problem solving can be represented in several ways:

The following ways:

1) Algorithm

2) Flow chart

3) Pseudo code

4) Decision table

5) Program

1) Algorithm:

Sequences of instructions that carryout in step by step manner in English language.

2) Flow Chart:

Pictorial representation of algorithm using standard symbols.

3) Pseudo Code:

Rules of structured design & programming.

4) Decision Table:

Nested selection to help clarify the conditions to be tested & proper actions.

5) Program:

The algorithm can be represented using high level language.

1) Algorithm:

Sequence of instructions that carry out in a step by step manner.

The algorithm is used to refer the logic of the program.

It is one of the basic tool used to develop the problem solving.

Characteristics:

Each & every instructions should be precise (perfect)

The instructions should not be repeated

Ensure that the algorithm will terminate

It should be written in sequence.

It should be in English.

Qualities of good algorithm:

The following factors are considered & measure the good algorithm.

1) Time: lesser time will take to execute the program.

2) Memory: lesser memory will take to execute the program.

3) Accuracy: program more accurate results.

4) Sequence: it must form in a sequence.

5) Generality: it designed to handle a range of input data to meet criteria.

So that algorithm must be generalized.

2. Flow chart:

It is diagrammatic represents the sequence of operations using standard symbols.

Draw the diagram oriented representation using symbols like as oval, parallelogram, rectangle, etc....,

Aim of flow charts:

It is easier to understand.

Easy to analyze &compare various methods.

It provides effective programming documentation.

It assists in reviewing & debugging.

Programming preparation can be simplified using the flow chart.

Flow chart symbols:



Rules for drawing flow chart:

The standard symbols only are used.

Flow of procedures is from top to bottom or left to right.

Direction of flow of control must represent.

Only one line will come & out from the process symbol.

Only one flow line enters to decision symbol, two or three flow will be out.

Every program must present the start & stop terminal symbol

Flow lines should not cross each other.

Addition symbols:

START

STOP



Basic design structure:

Design the structure to getting solution for problem.

There are three design structures are

1) Sequence

2) Selection

3) Loop

1) Sequence Structure:

It is the simples because it is series of statements performed one after another

Only one direction of every time execution.

2) Selection Structure:

Selection structure takes decision for select the control flow

It may be two exist TRUE OR FALSE separately process & rejoin in any point.

Otherwise TRUE value only process some statement & join in next statement.

3) Loop Structure:

It is used to execute a sequence of steps in number of times until condition is met.

there are two types of loops:

1) Top tested loop

2) Bottom tested loop.

Sequence Structure Selection Structure

FALSE TRUE IF(A>B)

PRINT “A IS BIG” PRINT “B IS BIG”

START

READ

PROCESS

OUTPUT

STOP



1) Top tested loop

It is evaluated statement is first then TRUE only flows lines goes into loop statements.

Otherwise FALSE will not enter to loop statements.

2) Bottom tested loop:

Decision will take at least once loop of statement executed

After executed loop condition check then TRUE means again enter in to loop otherwise exit the loop.

Top tested loop Bottom tested loop

Pseudo code:

It is written in normal English & cannot be understand by the computer.

Set of statements or instructions written in programming language.

It is also called Program Design Language(PDL)

Rules:

Write one statements per line.

Capitalize keywords.

End multiline structure(if,else,while,)

Indent show hierarchy

Keep statements language independent.

Advantages:

It is simple to use.

Disadvantages:

It is not visual.

Example:

Pseudo code for Factorial:

Set initial one to F, i

READ N value to find factorial

IF (i<=N) THEN

F = F * i

i = i + 1

ENDIF

WRITE the factorial of the number.

Stop

Draw the flow chart to find biggest of two numbers.

FALSE TRUE Evaluating

Condition

Block of Statements

Initialization

OUTPUT

STOP

START

READ A,B



Convert the (756)10 to octal and hexadecimal

Quotient Reminder 756

8 94 4

94

8 11 6

11

8 1 3

(756)10 = (1364)8


16 47 4

47

16 2 13

(756)10 = (2D4)16

Find the octal equivalent of the number (10111001100.1101011)2

010 111 001 100 . 110 101 100

2 7 1 4 . 6 5 4

(10111001100.1101011)2 = (2714.654)8

Find the decimal equivalent of the hexadecimal number 4D.C8.

(4D.C8)16 = (77.78125)10

8 x 16-2 8 x 1

256 0.03125

12 x 16-1 12 x 1

16 0.75000

13 x 160 13 x 1 13.00000

4 x 161 4 x 16 64.00000

77.78125



How will you convert CAB in hexadecimal to binary?

C A B

1100 1010 1011

(CAB)16 = (110010101011)2

Convert the following numbers into their binary equivalents: FAC16, 5618

FAC16 = (111110101100)2

F A C

1111 1010 1100

(561)8 = (101110001)2

5 6 1

101 110 001

Convert the decimal number 59.8125 into binary and octal.

59.8125 into binary


2 29 1

29

2 14 1

14

2 7 0

7

2 3 1

3

2 1 1

0.8125 X 2 1.625 1

0.625 X 2 1.25 1

0.25 X 2 0.5 0

0.5 X 2 1.0 1

(59.8125)10 = (111011.1101)2

59.8125 into octal


8 7 3

0.8125 X 8 6.5 6

0.5 X 8 4.00 4

(59.8125)10 = (73.64)8

Draw the flow chart and write an algorithm to compute area and circumference of circle.

ALGORITHM: FLOW CHART:

Step1: Start the program.

Step2: Get the Radius R as input.

Step3: Find Area and Circumference

Area 3.14 * R * R

Circumference 2 * 3.14 * R

Step4: Print the Area and Circumference.

START

READ R

AREA = 3.14 * R * R

CIRCUMFERENCE = 2 * 3.14 *R



Step5: Stop the program.

Draw the flow chart and write an algorithm to compute the student details.



Step2: Read the Marks for E, T, G, P, C, and M as input.

Step3: Find Total and Percentage

Total E+T+G+P+C+M

Percentage (Total/1200)*100

Step4: Print the Total and Percentage.


Write an algorithm, Flow chart and psuedocode to compute factorial of a number.



Step2: Read the n as input.

Step3: Set initial values F = i= 1.

Step4: IF i<=n else goto Step5

Step4.1: F F * i

Step4.2: i i + 1

Step5: Goto step4.

Step6: Otherwise print the F.


Draw a flow chart to find sum first 100 natural numbers.



Step2: Set initial values SUM = i= 0.

Step3: IF i<=100 else goto Step5

Step3.1: SUM SUM + i

Step3.2: i i + 1

START

READ E, T, G, P, C, M

STOP

Total = E+T+G+P+C+M

Percentage = (Total/1200)*100

PRINT Total,

Percentage

FALSE TRUE

START

READ N

IF (i<=N)

PRINT F

STOP

F = i = 1

F = F * i i = i + 1

START

SUM = i = 0



Step4: Goto step3.

Step5: Otherwise print the SUM.


Draw the flow chart and write an algorithm to find roots of quadratic equation.



Step2: Read the values for a, b, c as input.

Step3: Find the value of D.

D b * b – (4 * a * c)

Step4: IF D is greater than or equal to zero than find the roots

Root1 (-b + sqrt(D)) /(2 * a)

Root2 (-b - sqrt(D)) /(2 * a)

Step5: Print the Root1, Root2.

Step6: IF D is not greater than or equal to zero,

then print roots are imaginary.


UNIT-2

History of ‘C’ language:

‘C’ is one of the most popular programming languages; it was developed by Dennis Ritchie

at AT & T’s Bell Laboratories at USA in 1972.

FALSE TRUE

START

READ a,b,c

STOP

D = b * b – (4 * a * c)

PRINT Root1,

Root2

IF (D>=0)

Root1 = (-b + sqrt(D)) /(2 * a)

Root2 = (-b - sqrt(D)) /(2 * a)

PRINT Roots

are Imaginary



‘C’ IS A MIDDLE LEVEL LANGUAGE

Low level language: o Low level language is in terms of 0’s and 1’s.

o ‘C’ language has the certain features of “low-level language” that allows the

programmer to carry out operations on bits that are normally available in assembly or

machine language.

High level language: o High level language looks like normal English, whose instruction set is more

compatible with human languages.

o These languages are machine independent. Ex are FORTRAN, PASCAL, COBOL,

BASIC, C, C++,…..etc

C stands in between these two categories. It is neither a low level language nor a high level

language. It is a middle level language.

It means it performs the task of low level language as well as high level language.

We can write the codes for operating system, application programs, and assembly language

programs in ‘C’ language.

UNIX operating system is written in ‘C’ language.

FEATURES AND APPLICATIONS OF ‘C’ LANGUAGE:

1. ‘C’ is a general purpose, structured programming language.

2. ‘C’ is powerful, efficient, compact, portable and flexible.

3. ‘C’ is well suited for writing system software as well as application software.

4. ‘C’ program can be run on different operating systems of the different computers with little

or no alteration.

5. ‘C’ is a middle level language, i.e, it supports both the low level and high level language

features.

6. ‘C’ language allows manipulation of data at the lowest level i.e bit level manipulation. This

feature is extensively useful in writing system software program.

7. ‘C’ is a widely available, commercial ‘C’ compilers are available on most PC’s.

8. ‘C’ programs are fast and efficient.

9. ‘C’ has got rich set of operators.

10. ‘C’ can be applied in systems programming areas like compilers, Interpreters and Assemblers

etc.

STRUCTURE OF A ‘C’ PROGRAM

Documentation section

Preprocessor section

Definition section

Global declaration section

Void Main()

{

Declaration part;

Executable part;

}

Sub program section

{

Body of the sub program;

}

Documentation section:

It contains a set of comment lines used to specify the name of program the author and

other details etc.,

Comments:



Comments are very helpful in identifying the program features and underlying logic of

the program.

The single line comments using “\\”.

The lines begins with ‘/*’ and ending with ‘*/’ are known as comment lines. These are

not executable, the compiler is ignored anything in between /* and */.

Preprocessor section:

It is used to link system library files for defining the macros and for defining the

conditional inclusion.

Eg: #include<stdio.h>, #define A 10, #if def, #endif….etc.

Global declaration section:

The variables that are used in more than one function throughout the program are called

global variables and declared outside of all the function i.e., before main().

Every ‘C’ program must have one main() function, which specify the starting of ‘C’

program. It contains the following two parts.

Various elements of ‘C’ program:

Comment: /* program for temperature conversion */

Header file: #include<stdio.h>

Preprocessor directories: #define con 1.8 //Constant

Reserved words: int main ()

{

Variable type: float c,f //Standard identifiers

printf(“enter the Celsius values…….”);

Control string: scanf(“%f”, &c);

Special character: f = (con * c)+32;

Execution character: printf(“\n Fahrenheit value of the given %f Celsius value is

%f”, c,f);

Reserved word: return(0);

}

Declaration part:

This part is used to declare all the variables that are used in the executable part of the

program and these are called local variables.

Executable part:

It contains atleast one valid ‘C’ statement.

The execution of a program begins with opening brace ‘{‘and ends with closing brace

‘}’.

The closing brace of the main function is the logical end of the program.

All the statements in the program ends with a semicolon(;) except conditional and control

statements.

PROGRAMMING RULES:

All statements in ‘C’ program should be written in lower case letters.

Blank spaces may be inserted between the words. It is not used while declaring a variable,

keyword, constant and function.

The program statement can write anywhere between the two braces following the declaration

part.

The user can also write one or more statements in one line separating them with a

semicolon(;).

EXECUTING A ‘C’ PROGRAM

Execution is the process of running the program, to execute a ‘C’ program we need to

follow the steps given below.

1. Creating the program.

2. Compiling the program.



3. Linking the program with system library.

4. Executing the program.

Creating the program:

It means entering and editing the program in standard ‘C’ editor and save the program with

.C as an extension.

Compiling the program:

This is the process of converting the high level language program into machine

understandable form(Machine language). For this purpose compiler is used.

Usually this can be done in ‘C’ language by pressing ALT+F9 or choose compile option in

the menu system.

Here there is a possibility to show errors i.e., syntax errors, means the statements written in

program are not in proper syntax.

Linking the program with system library:

‘C’ language program is the collection of predefined functions. These functions are already

written in some standard ‘C’ header files. Therefore before executing a ‘C’ program, we

need to link with system library. This can be done automatically at the time of execution.

Executing the program:

This is the process of running and testing the program with sample data. At this time there

is a possibility to show two types of errors given below.

Logical errors: these are the errors, in which the conditional and control statements cannot end

their match after some sequential execution.

Data errors: these are the errors, in which the input data given, is not in a proper syntax as

specified in input statements.

Usually executing the program can be done by pressing CTRL+F9 or choose run option

from the menu system.

‘C’s CHARACTER SET

The character set is the any language and they are used to represent information.

Like natural languages, computer language will also have well defined character set, which

is useful to build the programs.

Thus learn to combine these alphabets to plan for words which in turn are combined to

form sentences and sentences are combined to form paragraphs.

Similarly the characters used to write ‘C’ program are basically of two types, namely

i. Source character set

ii. Execution character set

Source character set

These are used to construct the statements in the source program.

These are of four types

Source character

set

Notation

Alphabets A to Z and a to z

Decimal digits 0 to 9

White spaces Blank space, horizontal tabs, vertical tab, new line, form feed.

Special characters +, -, *, /, ;, ~, < , > , {, }, =, @, % .

Execution character set:

These are employed at the time of execution. This set of characters are also called as non

graphic characters because, these characters are invisible and cannot be printed or

displayed directly.

These characters will have effect only when the program is being executed.

Execution characters set are always represented by a backslash(\) followed by a character.

These are also called as ‘escape sequences’.

Character Escape sequence Result



Bell(Alert) \a Beep sound

Backspace \b Moves previous position

Horizontal tab \t Moves next horizontal tab

Vertical tab \v Moves next vertical tab

New line \n Moves next line

Form feed \f Moves initial position of next page

Carriage return \r Moves beginning of the line

C TOKENS:

The tokens are usually referred as individual text and punctuation in a passage of text.

The ‘C’ language program can contain the individual units called the C tokens and has

the following types.

1. Identifiers

2. Keywords

3. Constants

4. Strings

5. Operators

6. Special symbols

1. IDENTIFIERS

Identifiers are names given to various program elements, such as variables, functions and

arrays etc.

Rules:

Identifiers consist of letters and digits in any order.

The first character must be a letter/character or may begin with underscore( _ ).

Both upper/lower cases are permitted although uppercase character is not equivalent to

corresponding lowercase character.

The underscore ‘ _’ can also be used and is considered as a letter.

An identifier can be of any length while most of the ‘C’ compiler recognizes only the first

31 characters.

No space and special symbols are allowed between the identifier.

The identifier cannot be a keyword.

Valid identifiers:

STDNAME, SUB, Y2K.

Invalid identifiers:

STD NAME, Return, $stay, 7rno.

2. KEYWORDS:

There are certain reserved words called keywords that have standard and predefined

meaning in ‘C’ language which cannot be changed and they are the basic building blocks

for program statements.

Keywords are must written in lower case.

The ‘C’ keywords are listed below.

1. auto

2. break

3. case

4. char

5. const

6. continue

7. default

8. do

9. double

10. else

11. enum

12. extern

13. float

14. for

15. goto

16. if

17. int

18. long

19. register

20. return

21. short

22. signed

23. sizeof

24. static

25. struct

26. switch

27. typedef

28. union

29. unsigned

30. void

31. volatile

32. while

Data types:

Data type is the type of the data, that are going to access within the program.



Each data type may have predefined memory requirement and storage representation.

Primary User defined Derived Empty

char

int

float

double

typedef

Arrays

pointer

structures

union

void

The bytes occupied by each of the primary data types are

Data type Description Memory Control

string

Ex

int Integer quantity 2 bytes %d int a=39;

char Single character 1 byte %c char s = ‘n’;

float Floating pointing no’s. 4 bytes %f float f=29.77

double Double floating pointing

no’s.

8 bytes %lf double d=

29771770776

All C compilers supports the five fundamental data types called int, char, float, double

and void.

The primary data types are divided into the following.

INTEGER TYPE

Integers are the numbers with the supported range.

Usually the integers occupy one word of storage typically 16 or 32 bits.

The size of the integer depends upon the system.

signed unsigned

int unsigned int

short int unsigned short int

long int unsigned long int

CHARACTER TYPE

Characters are generally stored in 8 bits and a single character can be defined as char data

type.

char signed char unsigned

char FLOAT TYPE

The floating point numbers are generally stored in 32 bits with the 6 digits of precision.

The double datatype uses the 64bits with the 14 digits of precision.

float double long double

EMPTY DATA TYPE

The void is the null data type in ‘C’ language.

This is generally specified with the function which has no arguments.

void

VARIABLES:

A variable is an identifier that is used to represent some specified type of information.

Variable name give to relate the program.

i) Variable declaration:

We must declare them in a program, and this declaration tells the compiler what the

variable name and type of the data that the variable will hold.

Syntax: datatype variable-1,variable-2,…,variable-n;

Example: int code; char sex; float price;

ii) Initializing variables:

Initialization of variables can be done using the assignment operator ( = ).

Syntax: Datatype Variable = value;

Example: int i=29;

SCOPE OF VARIABLES:



Local variables:

The variables which are defined inside a main function block or inside a function are

called local variables.

It is declared within blocks.

Example:

void main()

{

int i,j;

/* body of the function */

}

Global variables:

The variables that are declared before the function main() are called the global variables.

Example:

int a=5,b=2;

void main()

{

fun();

}

void fun()

{

int sum;

sum = a+b;

}

STORAGE CLASSES:

1. Auto:

They are called as the automatic because their memory space is automatically allocated

as the variable is declared.

It is optional keyword.

Syntax: Storage_class_type data_type var1, var2……var n;

Example: auto int a,b;

2. Static:

The static variables are the variables for which the contents of the variables will be

retained throughout the program.

These are permanent within the function in which they are declared.

Syntax: Storage_class_type data_type var1, var2,…….varn;

Example: static int a,b;

3. Extern:

The external variables are declared out of the main() function the availability of these

variables are throughout the program and that is both in main program and inside the user

defined functions.

Syntax: Storage_class_type data_type var1, var2,……var n;

Example: extern int a, b;

4. Register:

Registers are special storage areas within a computer’s central processing unit.

The actual arithmetic and logical operation that comprise a program are carried out

within these registers.

Syntax: Storage_class_type data_type var1, var2, ………..var n;

Example: register int a,g;

CONSTANTS:



The item whose values cannot be changed during the execution of program are called

constants.

a) Numeric constants:

i) Integer constants:

An integer constant formed with the sequence of digits.

There are three types of integer constants which forms different number system.

Syntax: const datatype identifier=value;

Example: const int M = 95;

Rules:

It must have atleast one value.

Decimal point is not allowed.

It can be either positive or negative.

ii) Real constants:

A real constant is made up of a sequence of numeric digits with presence of a decimal

point.

Real constants serve as represent quantities such as distance, heights, temperatures, etc.

Syntax: const datatype identifier=value;

Example: const float distance =126.5;

Rules:

A real constant must have one digit.

A real constant must have decimal point.

No commas or blank spaces are allowed.

b) Character constants:

i) Single character constants:

The character constant contains a single character enclosed within pair of single inverted

commas(‘) both pointing to the left.

Syntax: const datatype identifier= value;

Example: const char c=’s’,gender=’F’;

ii) String constants:

A string constant is a sequence of characters enclosed in double quotes the characters

may be letters, numbers, special characters and blank spaces etc.

Syntax: const datatype identifier= value;

Example: const char c[10]=”senthil”;

Delimiters:

These are the symbols, which has some syntactic meaning and has got significance.

Symbol Name Meaning

# Hash Pre-processor directive

, Comma separate list of variables

: Colon Label

; Semi colon Statement end

( ) Parenthesis Function and Expression

{ } Braces Creating blocks

[ ] Square bracket Arrays

Statements:

Statements can be defined as set of declaration or sequence of action. Statement causes

the computer to perform some action.

1. Assignment statements:

Assignment operator used for assigning values to the variables.

Example: basic =3890;

2. Null statements:

A statement without any characters and it has only semicolon is called null statement.



Example: ; (null statement)

3. Block of statements:

Block contains several statements that are enclosed within a pair of braces {}.

These can be any of expression, assignments and keywords etc.

Example:

{

int a=890;

float b= 89.9;

printf(“%d%f”, a, b);

}

4. Expression statements:

These consist of expressions and can be arithmetic, relational or logical.

Example: a= 29

B=a+77;

fun(a,b);

OPERATORS

An operator is as symbol that specifies an operation to be performed on the operands.

The data items are called operands.

Example: a+b

‘+’ operator and a, b are the operands.

Types of operators:

1) Arithmetic Operator (+, -,*,/,%,)

2) Relational Operator (<,>,<=,>=,!=,==)

3) Logical Operators (&&.||,!)

4) Assignment Operator ( = )

5) Increment & decrement Operator (++,--)

6) Conditional (or) Ternary Operator (? , : )

7) Bitwise Operator (&,!,|,^)

8) Special Operator (, sizeof,&&*, .&->)

1) Arithmetic operators:

Basic arithmetic operation like addition, subtraction, multiplication, and division.

Operator Meaning Example A=9, B=5

+ addition C=a+b C=14

- subtraction C=a-b C=4

* multiplication C=a*b C=45

/ division C=a/b C=1

% Modulo C=a%b C=4

Example:

//Arithmetic Operators

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c,d;

clrscr();

printf("Arithmetic Operators");

printf("\nEnter the A & B Value:");

scanf("%d%d",&a,&b);

printf("A=%d\nB=%d",a,b);



c=a+b;

printf("\nAddition = %d",c);

c=a-b;

printf("\nSubtraction = %d",c);

c=a*b;

printf("\nMultiplication = %d",c);

c=a/b;

printf("\nDivision = %d",c);

c=a%b;

printf("\nModulo = %d",c);

getch();

}

OUTPUT: Arithmetic Operators

Enter the A & B Value:9

5

A=9

B=5

Addition = 14

Subtraction = 4

Multiplication = 45

Division = 1

Modulo = 4

Unary arithmetic: it requires only one operand.

Ex: +x

Binary arithmetic: it requires two operands.

Ex: a+b

2) Relational operators:

Relational operators are used to compare two or more operands.

Operands may be variables, constants or expression.

The value of relational expression is either one or zero.

Relational operators are used in decision making process.

Operator Meaning Example A=9, B=5

< Less than C=a<b C=0

> Greater than C=a>b C=1

<= Less than or Equal to C=a<=b C=0

>= Greater than or equal to C=a>=b C=1

== Equal to C=a==b C=0

!= Not equal to C=a!=b C=1

Example:

//Relational Operators

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

printf("Relational Operators");






c=a>b;

printf("\nGreaterthan (>)= %d",c);

c=a<b;

printf("\nLessthan (<)= %d",c);

c=a>=b;

printf("\nGreaterthan or equal (>=)= %d",c);

c=a<=b;

printf("\nLessthan or equal (<=)= %d",c);

c=a==b;

printf("\nEqual to (==)= %d",c);

getch();

}

OUTPUT: Relational Operators


5

A=9

B=5

Greaterthan (>)= 1

Lessthan (<)= 0

Greaterthan or equal (>=)= 1

Lessthan or equal (<=)= 0

Equal to (==)= 0

3) Logical operators:

Logical operators are used to combine the results of two or more conditions.

The logical operators are &&, ||,!

Syntax: (exp1)&&(exp2)

Operator Meaning Example A=9, B=5, C=2

&& Logical AND d=(a>b)&&(a>c) d=1

|| Logical OR d=(a>b)||(a>c) d=1

! Logical NOT d=!(a>=b) d=0

Example:

//Logic Operators

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c,d;

clrscr();

printf("Logic Operators");

printf("\nEnter the A,B,C Value:");

scanf("%d%d%d",&a,&b,&c);

printf("A=%d\nB=%d\nC=%d",a,b,c);

d=(a>b)&&(a>c);

printf("\nLogic AND\n((a>b)&&(a>c)) = %d",d);

d=(a>b)||(a>c);

printf("\nLogic OR\n((a>b)||(a>c)) = %d",d);

d=!(a>=b);

printf("\nLogic NOT\n(!(a>=b)) = %d",d);

getch();

}

OUTPUT: Logic Operators



Enter the A,B,C Value:9

5

2

A=9

B=5

C=2

Logic AND

((a>b)&&(a>c)) = 1

Logic OR

((a>b)||(a>c)) = 1

Logic NOT

(!(a>=b)) = 0

4) Assignment operators:

Assignment operators are used to assign a value or an expression or a value of a variable

to another variable.

Example: x=5;

i) Compound assignment:

Compound assignment operators to assign a value to a variable in order to assign a new

value to a variable after performing a specified operation.

Example: x+ = y

ii) Nested assignments:

‘C’ language has got distinct features in assignment called nested assignment.

Syntax:

var1=var2=…………..var-n= single variable or expression or value;

Example: i=j=k=l;

x=y=z=(i+j+k);

5) Increment or decrement operators:

++ and -- are the increment and decrement operator.

These operators are called unary operators.

Pre increment or pre decrement: First increment or decrement the value after assign or

operate.

post increment or post decrement: Assign or operate after increment or decrement

Operator Meaning Example A=5

++a Pre increment printf(“A=%d”,++a) A=6

--a Pre decrement printf(“A=%d”,--a) A=5

a++ Post increment printf(“A=%d”,a++) A=5

a-- Post decrement printf(“A= %d”,a--) A=5

6) Conditional operator:

It checks the condition and executes the statement depending on the condition.

It is like as if…else statement.

Syntax:

Condition?exp1:exp2;

Example:

int a=5,b=3,big;

big=a>b?a:b;

printf(“%d is big”,big);

7) Bitwise operators:

It is used to manipulate the data at bit level.

It operates on integer only.



It may not be applied to float or real.

a) Bitwise AND(&):

This operator is represented as ‘&’ and operates on two operands of integer type.

Truth table for &:

A B A&B

0 0 0

0 1 0

1 0 0

1 1 1

b) Bitwise OR(|):

This operator gives if either of the operand bit is ‘|’ then result is ‘1’ or both operands are

1’s then also given ‘1’.

A B A|B

0 0 0

0 1 1

1 0 1

1 1 1

c) Bitwise exclusive OR(^):

Similar to AND operator in all aspects but integer gives if either of the operand bit is

high(1) then it gives high(1) result.

If both operand bits are same then it gives

low(0) result.

For all the above operators in all possible combinations of bits as shown below.

A B A|B A&B A^B ~A

0 0 0 0 0 1

0 1 1 0 1 1

1 0 1 0 1 0

1 1 1 1 0 0

Example:

//Bitwise OPerators

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

printf("Bitwise Operators");




c=a&b;

printf("\nBitwise AND (&) = %d",c);

c=a|b;



printf("\nBitwise OR (|) = %d",c);

c=a^b;

printf("\nBitwise EX-OR (^) = %d",c);

c=~a;

printf("\nOne's Complement or Bitwise NOT (~) = %d",c);

c=a<<2;

printf("\nLeft Shift (<<)= %d",c);

c=a>>2;

printf("\nRight Shift (>>)= %d",c);

getch();

}

OUTPUT: Bitwise Operators


3

A=7

B=3

Bitwise AND (&) = 3

Bitwise OR (|) = 7

Bitwise EX-OR (^) = 4

One's Complement or Bitwise NOT (~) = -8

Left Shift (<<)= 28

Right Shift (>>)= 1

8) The special operator:

1. Comma operator(,):

It is used to separate the statement elements such as variables, constants or expression

etc.

Example: val = (a=3, b=9, c=77, a+c);

2. Sizeof() operator:

it is a unary operator, that returns the length in bytes of the specified variable, and it is

very useful to find the bytes occupied by the specified variable in the memory.

It is a compile time operator.

Syntax:

sizeof(var);

Ex:

void main()

{

int a;

printf(“size of variable a is……..%d”, sizeof(a));

}

Output:

size of variable a is…………2

3. Pointer operators:

&---This symbol specifies the address of the variable.

* --- This symbol specifies the value of the variable.

4. Member selection operators:

. and -- > : These symbols used to access the elements from a structure.

EXPRESSIONS:

An expression represents data item such as variables, constants and are interconnected

with operators as per the syntax of the language.

An expression is evaluated using assignment operator.

Syntax: variable = expression;

Example: x=a*b-c;



Arithmetic operator’s precedence:

Arithmetic operators are evaluated from the left to right using the precedence of operators

when the expression is written without the parameters.

High:* / %

Low: + -

First phase: the highest priority operators are evaluated in the expression.

Second phase: the lowest priority operators are evaluated in the expression.

Type conversion:

It refers to the process of changing an entity of one data type into another.

i) Implicit conversion:

It is an automatic type conversion. In a mixed type expression data of one or more subtypes

can be converted to a super type as needed at runtime so that the program will run correctly.

Example:

int c;

float f=3.5;

c=f;

printf(“%d”,c);

OUTPUT:

3

ii) Explicit conversion:

The explicit conversion can be made possible to convert one data type to another by

forcefully and it is different from the implicit conversion.

Syntax: var1=(datatype)var2;

Ex: int a=10;

float(a);

Where a=10;

float (a) will contain 10.000000

MANAGING INPUT AND OUTPUT OPERATIONS

INPUT OUTPUT STATEMENTS

We know that input, process, output are the three essential features of computer program.

The program takes some input data processes it and gives the output.

We have two methods for providing data to the program.

o Assigning the data to the variables in a program.

o By using the Input/Output statements.

In ‘C’ language, two types of Input/Output statements are available, and all input and output

operations are carried out through function calls.

Several functions are available for input/output operations in ‘C’.

These functions are collectively known as the standard I/O library.

i) Unformatted Input/Output statements

ii) Formatted Input/Output statements

Input / Output

Unformatted I/O Formatted I/O

Input

getchar() getc() gets() getch() getche()

Output

putchar() putc() puts()

Input

scanf() fscanf()

Output

printf() fprintf()



UNFORMATTED INPUT/OUTPUT STATEMENTS

1) getchar() function:

A single character can be given to the computer using ‘C’ input library function getchar().

Syntax: char variable = getchar();

Example: char x;

x= getchar();

The getchar() function is written in standard I/O library.

It reads a single character from a standard input device.

This function do not require any arguments, through a pair of empty parenthesis, must follow

the statement getchar().

2) putchar() function:

The putchar() function is used to display one character at a time on the standard output

device.

Syntax: putchar(char variable);

Example: char x;

putchar(x);

3) getc() function:

This is used to accept a single character from the standard input to a character variable.

Syntax: char variable = getc();

Example: char c;

c= getc();

4) putc() function:

This is used to display a single character in a character variable to standard output device.

Syntax: putc(char variable);

Example: char c;

putc(c);

5) gets() function:

The gets() function is used to read the string from the standard input device.

Syntax: gets(char type of array variable);

Example: gets(s);

6) puts() function:

The puts() function is used to display/write the string to the standard output device(Monitor).

Syntax: puts(char type of array variable);

Example: puts(s);

7) getch() function:

The getch reads a single character directly from the keyboard without echoing to the screen.

Syntax: int getch(void);

8) getche() function:

The getche reads a single character from the keyboard and echoes it to the current text

window.

Syntax: int getche(void);

Character test functions:

Function Test

isalnum(ch) Is ch an alphanumeric character?

isalpha(ch) Is ch an alphabetic character?

isdigit(ch) Is ch a digit?

islower(ch) Is ch a lowercase letter?



toupper(ch) Convert ch to uppercase.

isupper(ch) Is ch a uppercase letter?

isspace(ch) Is ch a blank space character?

tolower(ch) Convert ch to lowercase.

FORMATTED INPUT/OUTPUT STATEMENTS:

Formatted input/output refers to input and output, that has been arranged in a particular

format.

INPUT OUTPUT

scanf() printf()

fscanf() fprintf()

a) scanf() function:

Input data can be entered using the standard input library function called scanf().

This function is used to enter any combination of input.

The scanf() function is used to read information from the standard input device, scanf() starts

with a argument and may contain additional arguments.

Syntax: scanf(“control string”, &var1,…………&var-n);

Example: int n;

scanf(“%d”, &n);

Control string:

It is the type of data to accept via the input statements, this can be formatted and always

preceded with a ‘%’ sign.

Format code Meaning

%c Single character

%d integer

%s Strings

%f Float values

Rules:

The control string must be preceded with % sign and must be within quotations.

If there is a number of input data items, items must be separated by commas and must be

preceded with & sign except for string input.

The control string and the variables going to input should match with each other.

It must have termination with semicolon.

b) printf() function:

Output data or result of an operation can be displayed to a standard output device using the

library function printf().

This function is used to output any combination of data.

It is similar to the input function scanf(), except that it display data rather than input.

There are two types of printf() functions:

1. printf() with control string

2. printf() without control string

Syntax: printf(“control string”, var1, var2,…………var n);

Example: printf(“result is…….%d”, n);

printf(“%f”,f);

printf(“%s”,s);

Rules:

The variable must be separated by commas, and need not be preceded with ‘&’ sign.

The control string and the variables must match in their order.

The control string must be in quotations and there also use any other text to print with data.

Provide blank space in between the numbers for better readability.



Print special messages wherever required in output.

fscanf() and fprintf():

fscanf() and fprintf() functions are used only during the file operations.

fscanf()---for reading the content from file.

fprintf()---for writing the content to the file.

Reading and writing integer numbers:

The integers can be read/write through the scanf() and printf() statements with the field

specification along with the control string.

Reading:

The scanf() function reads the integer numbers using its format specification ‘%d ’

Syntax: scanf(“%d” , &var);

Example: scanf(“%d%d”, &x, &y);

Writing:

The integer data values can also be displayed using the field width specification in

printf() statement.

Syntax: printf(“%d”, var);

Example: printf(“%d”, x);

Reading and writing real or floating point numbers:

Reading:

The scanf() function reads the real numbers using its format specification ‘%f ’

Syntax: scanf(“%f” , &var);

Example: scanf(“%f%f”, &x, &y);

Writing:

The writing or displaying of real numbers may be displayed in decimal point notation

using the field width specification.

Syntax: printf(“%(width)f” , var);

Example: printf(“%.2f”,x);

Reading and writing character strings:

The single character or string can be read/write through the scanf() and printf()

statements with the field specification along with the control string.

Reading a character:

The specification for reading character is %c

Syntax: scanf(“%c”, var);

Example: scanf(“%c”, gender);

Reading strings:

Specification for reading string is %s

Syntax: scanf(“%s”, var);

Example: scanf(“%s”, name);

Writing a character:

A single character can be displayed in a desired position using the following format.

Syntax: printf(“%c”, var);

Writing strings:

The writing or displaying of string may be displayed in decimal point notation using the

following width specification.

Syntax: printf(“ %s”, var);

Enhancing the readability of output:

Specify the blank spaces in between the data items whenever necessary and applicable.



Specify the appropriate headings and names for the variables.

Give the blank line as and when required.

Specify newline character whenever is applicable.

Print special text messages depending on necessity.

CONTROL STATEMENTS OR CONTROL STRUCTURES

Programmers can take decisions in their program with help of control statements.

Types of control statements:

1. Sequence (or) Linear Structure

2. Decision making (or) selection (or) Branching Structure

3. Looping (or) Iteration Structure

4. Unconditional Structure

S.No. Structure Name Types

1 Sequence (or) Linear Structure one by one

2 Decision making (or) Selection (or) Branching Structure

1. Simple if

2. If ….else

3. Nested if ….else

4. if……else ladder

5. Switch case

6. Nested switch case

3 Looping (or) Iteration Structure

1. while

2. do-while

3. for

4. Nested for

4 Unconditional Structure

1. break

2. continue

3. goto

4. return

1. Sequence (or) Linear Structure:

Statements are read one by one is called sequence or linear structure.

It is normal flow of program.

Only one direction of every time execution.

2. Decision making (or) selection (or) Branching Structure

a) Simple if statement

The if statement is a decision making statement.

It is used to control the flow of execution of the statements and also used to test logically

whether the condition is true or false.

It is always used in conjunction with condition.

This statement is used when a question requires answer.

Syntax Flow Chart Example



if(condition is true)

{

True statements;

}

Next Statement;

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b;

clrscr();

scanf(“%d%d”,&a,&b);

if(a>b)

{

printf(“A is big”);

}

printf(“\nIt is simple if”);

getch();

}

Properties:

If the condition is true then the simple or compound condition statements are executed.

If the condition is false it does not do anything.

The condition is given in parenthesis and must be evaluated as true or false.

If a compound structure is provided it must be enclosed in opening and closing braces.

b) The if-else statement:

It is basically two way decision making statement and always used in conjunction with

condition.

It is used to control the flow of execution and also used to carry out the logical test and

then pickup one of the two possible actions depending on the logical test.

Syntax Flow Chart Example

if(condition)

{

True statements;

}

else

{

False statements;

}

Next Statement;

//Biggest of 2 Numbers

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b;

clrscr();


if(a>b)

{


}

else

{

printf(“B is big”);

}

printf(“\nIt is if…else”);

getch();

}

c) Nested if……..else statement:

When a series of if…..else statements are occurred in a program, we can write an entire

if…..else statement in another if….else statement called nesting and the statement is

called nested if.

Start

Read A,B

if(A>B)

Print “A is Big”

Print “It is simple if”

Stop

True

False

FALSE TRUE if(A>B)

PRINT “A IS BIG” PRINT “B IS BIG”

Start

Read A,B

Stop

Print “It is if…else”



Flow Chart:

Syntax Example

if(condition 1)

{

if(condition 2)

{

True statement2;

}

else

{

False statement2;

}

}

else

{

False statement1;

}

Next Statement;


#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

scanf(“%d%d%d”,&a,&b,&c);

if(a>b||c>b)

{

if(a>c)

{


}

else

{

printf(“C is big”);

}

}

else

{


}

printf(“\nIt is Nested if…else”);

getch();

}

d) if……else ladder:

Nested if statements can become quite complex.

More than three alternatives is not consistent to determine the logical structure of if

statement.

In situations, you can use the nested if as the else if ladder.

Flow Chart:

TRUE FALSE

Start

Read A,B,C

Stop

Print “It is Nested if…else”

FALSE TRUE if(A>B||C>B)

PRINT “A IS BIG”

PRINT “B IS BIG” if(A>C)

PRINT “C IS BIG”

TRUE

Start

Read A,B,C,D

FALSE if(A>B&&A>C&&A>D)



Syntax Example

if(condition 1)

{

Statement 1;

}

else if(condition 2)

{

Statement 2;

}

else if(condition 3)

{

Statement 3;

}

else

{

Default- statements;

}

Next Statement;


#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c,d;

clrscr();

scanf(“%d%d%d%d”,&a,&b,&c,&d);

if(a>b&&a>c&&a>d)

{


}

else if(b>c&&b>d)

{


}

else if(c>d)

{

printf(“C is big”);

}

else

{

printf(“D is big”);

}

printf(“\nIt is if…else Ladder”);

getch();

}

The switch statement:

The switch statement is used to pickup or execute a particular group of statements from

several available groups of statements.

It allows us to make a decision from the number of choices.



It is a multiway decision statement, it tests the value of given variable or expression

against a list of case values and when a match is found a block of statements associated

with that case is executed.

Flow Chart:

Syntax:

Syntax Example

switch(expression)

{

case constant-1:

Block 1;

break;

case constant-2:

Block 2;

break;

.

.

default:

Default block;

break;

}

Next Statement;

//Arithmetic operations using switch case

#include<stdio.h>

#include<conio.h>

void main()

{

int a=10,b=20,ch,d;

clrscr();

printf("1.ADD\n2.SUB\n3.MUL\n4.DIV");

printf("\nEnter your choice:");

scanf("%d",&ch);

switch(ch)

{

case 1:

printf("%d",a+b);

break;

case 2:

printf("%d",a-b);

break;

case 3:

printf("%d",a*b);

break;

case 4:

printf("%d",a/b);

break;

default:

printf("\nEnter the correct choice");

break;

}

printf("\nIt is switch case");

CH=3

CH=4

CH=2

CH=1

Start

Read CH

Initialize A=10,B=20,C=0,CH

switch(CH)

Print C=A+B

Print C=A-B

Print “1.ADD 2.SUB 3.MUL 4.DIV”

Print C=A*B

Print C=A/B

Stop



getch();

}

Rules:

The expression in switch statement must be an integer value or a character constant.

No real numbers are used in an expression.

The case labels must be constants.

The switch can be nested.

Nested switch() case:

‘C’ supports the nested switch() statements. The inner switch() statement can be a

part of an outer switch() statement.

The inner and outer switch() case constants may be same.

No conflict arises even if they are same.

Comparison of switch() case and nested if:

Switch() case Nested if

The switch() can test only constant values. The if can evaluate relational or logical

expressions.

No two case statements have identical

constants in the same switch.

Same conditions may be repeated for number of

times.

Character constants are automatically

converted to integers.

Character constants are automatically converted

to integers

In switch() case statement, nested if can be

used.

In nested if statements switch() case can be used.

LOOPING STATEMENTS:

1. while loop:

It is a repetitive control structure, used to execute the statements within the body until the

condition becomes false.

The while loop is an entry controlled loop statement means the condition is evaluated first

and it is true then the body of the loop is executed.

After executing the body of the loop the condition is once again evaluated and if it is true,

the body is executed once again the process of repeated execution of the body of the loop

until the condition becomes false and the control is transferred out of the loop.

The body of the loop may have one or more statements the blocking with the braces are

needed only if the body contains two or more statements.

Syntax Example OUTPUT



while(condition)

{

Body of the loop;

}

void main()

{

int n,i,sum=0;

clrscr();

printf("Sum of n Numbers");

printf("\nEnter the Limit Value:");

scanf("%d",&n);

i=0;

while(i<=n)

{

sum=sum+i;

i++;

}

printf("\nSum = %d",sum);

getch();

}

Sum of n Numbers

Enter the Limit Value:10

Sum = 55

2. do……while loop:

The while loop makes a test of condition before the loop is executed.

In some situations it may be necessary to execute the body of the loop before the test condition

is performed, such a situation the do……while loop is useful.

It is also repetitive control structure and executes the body of the loop once irrespective of the

condition then it checks the condition and continues the execution until the condition is false.

Here the statements within the body of the loop are executed once, then it evaluates for the

condition if it is true, then it executes body until the condition becomes false.


do

{

Body of the loop;

}while(condition);

void main()

{

int n,i,sum=0;

clrscr();



scanf("%d",&n);

i=0;

do

{

sum=sum+i;

i++;

}while(i<=n);


getch();

}

Sum of n Numbers


Sum = 55

While Do……while

This is the top tested loop. This is the bottom tested loop.

The condition is first tested if the condition is

true then the block is executed until the condition

becomes false.

It executes the body once after it checks the

condition if it is true the body is executed

until the condition becomes false.

Loop will not be executed if the condition is

false.

Loop is executed at least once even though

the condition is false.

3. for loop:

The for loop is another repetitive control structure and is used to execute set of instructions

repeatedly until the condition becomes false.



The assignment incrementation or decrementation and condition checking is done in for

statement only where as other control structures are not offered all these features in one

statement.

For loop has three parts:

1. Initialize counter is used to initialize counter variable.

2. Test condition is used to test the condition.

3. Increment/decrement counter is used to increment or decrement counter variable.

If there is a single statement within the for loop the blocking with braces is not

necessary if more than one statement includes in body of the loop the statements

within the body must be blocked with braces.


for(initialize; condition;

increment/ decrement)

{

Body of the loop;

}

void main()

{

int n,i,sum=0;

clrscr();



scanf("%d",&n);

for(i=0;i<=n;i++)

{

sum=sum+i;

}


getch();

}

Sum of n Numbers


Sum = 55

4. Nesting of for loops:

Like if statement for loop also nested. The loop within the loop is called nested loop.

In nested loops two or more for statements are included in the body of the loop.

The number of iterations in this type of structure will be equal to the number of

iterations in the outer loop multiplied by the number of iterations in the inner loop.

Types of loops:

1. Counter controlled loops:

The counter controlled loops are used in a situation when the programmer knows

in prior exactly how many times the loop will be executed.

These loops are also called as definite repetition loop.

In this loop the control variable is declared initialized tested and updated regularly

for the designed operations.

2. Sentinel controlled loop:

The sentinel controlled loops are used in a situation when the programmer not

knows in prior exactly the number of times the loop will be executed.

This loop is also called as indefinite repetition loop, because the no. of repetition

is not known before.

In this loop the control variable is called sentinel variable it is tested with test

condition for repetition.

Ex:

While(i!=-999)

{

Scanf(“%d”, &i);

Sum = sum+i;

}

Selecting a suitable loop structure:

Choose either entry-controlled or exit controlled loop depending on the problem.



Choose either counter-controlled loop or sentinel controlled loop depending on

the problem.

If the entry-controlled loop is necessary the best suitable loop in while or for.

If the exit controlled loop is necessary the best suitable loop is do…..while.

Choose for loop for counter controlled loop and while for sentinel controlled

loops.

UNCONDITIONAL STATEMENTS:

1. break statement:

It is used to terminate the loop.

When the keyword break is used inside any ‘C’ loop control automatically transferred to the

first statement after the loop.

A break is usually associated with an if statement.

When the break statement is encountered inside a loop the loop is immediately exited and

the program continues with the statement immediately following the loop.

Syntax: break;

2. continue statement:

In some situation we want to take the control to the beginning of the loop bypassing the

statements inside the loop which have not yet been executed, for this purpose the continue is

used.

Syntax: continue;

Break Continue

Break statement takes the control to the outside

of the loop.

Continue statement takes the control to the

beginning of the loop.

It is used in switch statement. It is used in loop statements.

Always associated with if condition in loops. This is also associated with if condition.

3. goto statement:

So far we have seen number of ways of controlling the flow of execution based on the

conditions.

‘C’ provides the goto statement to transfer control unconditionally from one place to another

place in the program.

A goto statement can cause program control almost anywhere in the program

unconditionally.

The goto statement requires a label to identify the place to move the execution.

A label is a valid variable name and must be ended with colon(:).

Syntax:

goto label;

label:

label:

goto label;

//Sum of n Numbers

#include<stdio.h>

#include<conio.h>

void main()

{

int n,i,sum=0;

clrscr();



scanf("%d",&n);



for(i=0;i<=n;i++)

sum=sum+i;


getch();

}

OUTPUT:

Sum of n Numbers


Sum = 55

//Sum and average Numbers

#include<stdio.h>

#include<conio.h>

void main()

{

int a[10],n,i,sum=0;

float avg=0.0;

clrscr();

printf("Sum and average of given Numbers");


scanf("%d",&n);

printf("\nEnter the Values:");

for(i=0;i<n;i++)

{

scanf("%d",&a[i]);

sum=sum+a[i];

}

avg=(float)sum/n;


printf("\nAverage = %.2f",avg);

getch();

}

OUTPUT:

Sum and average of given Numbers


Enter the Values:3

6

1

Sum = 10

Average = 3.33

//roots of quadratic equation.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c,D;

float Root1,Root2;

clrscr();

printf("Roots of quadratic equation.");

printf("\nEnter the A,B,C Value:");



scanf("%d%d%d",&a,&b,&c);

D=(b*b)-(4*a*c);

if(D>=0)

{

Root1=(float)(-b+sqrt(D))/(2*a);

Root2=(float)(-b-sqrt(D))/(2*a);

printf("\nRoot1 = %.2f",Root1);

printf("\nRoot2 = %.2f",Root2);

}

else

{

printf("\nRoots are imaginary");

}

getch();

}

OUTPUT:

Roots of quadratic equation.

Enter the A,B,C Value:3

10

2

Root1 = 463.00

Root2 = -466.33



UNIT-3

ARRAYS and STRINGS

Arrays:

An array is a collection of similar data items, which are stored under a common name.

Each element of an array is stored in successive locations of the memory.

Data items can be int, float, char values of data types.

The elements of the array are known as members of the array.

Arrays are declared using the symbol square bracket”[ ]” (or) subscript.

Need for Array:

A single variable store only one value.

If we want to store more values means we need to declare more variables.

This problem solved using array.

Types of array:

Arrays can be classified into

1. One Dimensional Array

2. Two Dimensional Array

3. Multi Dimensional Array

1. One Dimensional Array:

An array is a collection of similar data items, which are stored under a common name using

single subscript.

One Dimensional Array also called linear array or Single Dimensional Array.

The array elements must be accessed on an element by element.

Array accessed by using looping structure(for, while).

Array elements are always starting at Zero and end with Maximum element-1.

Syntax:

Datatype array_name[size];

Datatype—Type of data items like as int,char,float

Array_name---specifies name of the array

Size---element count.

Example: int a[3];

Array index Element values

a[0] 4

a[1] 12

a[2] 10

Array initialization:

The array initialized in two ways:

1. At compile time

2. At run time

1. At compile time:

o The array elements are initialized at the time of declaration.

Syntax: Datatype array_name[]={list of values};

Example: int marks[3]={45,67,89};

Array index Element values

marks[0] 45

marks [1] 67

marks [2] 89

2. At run time:

o The array elements are initialized at the time of program running.

o The “for” loop is used to initialize values for array element.

Example:

i) Using for loop to initialize value “0” to all the elements.

int a[10],i;

for(i=0;i<10;i++)

a[i]=0;



ii) Using scanf() function to initialize different values.

int a[5],i;

for(i=0;i<5;i++)

scanf(“%d”,&a[i]);

//One Dimensional array Sum and average Numbers

#include<stdio.h>

#include<conio.h>

void main()

{

int a[10],n,i,sum=0;

float avg=0.0;

clrscr();

printf("Sum and average of given Numbers");


scanf("%d",&n);

printf("\nEnter the Values:");

for(i=0;i<n;i++)

{

scanf("%d",&a[i]);

sum=sum+a[i];

}

avg=(float)sum/n;


printf("\nAverage = %.2f",avg);

getch();

}

OUTPUT:

Sum and average of given Numbers


Enter the Values:45

2

3

10

5

Sum = 65

Average = 13.00

2. Two Dimensional array:

o Two dimensional arrays have two subscripts.

o We need to store table of values use the 2D array.

o Two pairs of square brackets denoted by rows and columns.

Example: A[3][3];

Column-0 Column-1 Column-2

Row-0

Row-1

Row-2

That is represented as

Columns

Column-0 Column-1 Column-2

Row-0 A[0][0] A[0][1] A[0][2]

Row-1 A[1][0] A[1][1] A[1][2]

Row-2 A[2][0] A[2][1] A[2][2]

Syntax:

Datatype array_name[row_size][column_size];

Initialization:

R

ow

s



1. At compile time:

The values can be initialized at the time of declaration.

Syntax:

Datatype array_name[row_size][column_size]={List of Values};

Example:

A[2][2]={{1,2}{3,4}};

Or

A[2][2]={1,2,3,4};

2. At run time:

The values can be initialized at the time of running.

Run time initialization can be do with the scanf() function.

Example:

int a[5][5],I,j;

for(i=0;i<5;i++)

for(j=0;j<5;j++)

scanf("%d",&a[i][j]);

Example:

//Two Dimensional array or Matrix Multiplication

#include<stdio.h>

#include<conio.h>

void main()

{

int a[2][2],b[2][2],c[2][2],j,i,k;

clrscr();

printf("Matrix Multiplication");

printf("\nEnter the A matrix 4 values:");

for(i=0;i<2;i++)

for(j=0;j<2;j++)


printf("\nEnter the B matrix 4 values:");

for(i=0;i<2;i++)

for(j=0;j<2;j++)

scanf("%d",&b[i][j]);

printf("\nResult Matrix:\n");

for(i=0;i<2;i++)

{

for(j=0;j<2;j++)

{

c[i][j]=0;

for(k=0;k<2;k++)

c[i][j]= c[i][j]+a[i][k]*b[k][j];

}

}

for(i=0;i<2;i++)

{

for(j=0;j<2;j++)

printf("%d\t",c[i][j]);

printf("\n");

}

getch();

}

OUTPUT:

Matrix Multiplication

Enter the A matrix 4 values:1

2

3

4

Enter the B matrix 4 values:5

6



7

8

Result Matrix:

19 22

43 50

//Two Dimensional array or Matrix Addition

#include<stdio.h>

#include<conio.h>

void main()

{

int a[2][2],b[2][2],c[2][2],j,i;

clrscr();

printf("Matrix Addition");

printf("\nEnter the A matrix 4 values:");

for(i=0;i<2;i++)

for(j=0;j<2;j++)


printf("\nEnter the B matrix 4 values:");

for(i=0;i<2;i++)

for(j=0;j<2;j++)

scanf("%d",&b[i][j]);

printf("\nResult Matrix:\n");

for(i=0;i<2;i++)

{

for(j=0;j<2;j++)

{

c[i][j]=a[i][j]+b[i][j];

printf("%d\t",c[i][j]);

}

printf("\n");

}

getch();

}

OUTPUT:

Matrix Addition

Enter the A matrix 4 values:3

2

1

5

Enter the B matrix 4 values:4

6

8

2

Result Matrix:

7 8

9 7

Strings:

Group of (or) Collection of (or) Array of characters are called strings.

The strings are specified with pair of double quotes (“ “).

Where declaring a string it will take null character “\0” at the end of string.

This null character cannot visible.

Syntax: char array_name[];

Initialization:

The values of string can be initialized at run time or compile time.

The string values are initialized at compile time:

Syntax: char array_name[]=”values”;



Example: char name[]=”Senthil”;

The string values are initialized at run time using scanf():

Syntax:

char array_name[];

scanf(“%s”,array_name);

Example:

char name[];

scanf(“%s”,name);

Reading and Writing:

Reading & writing the string using scanf() & printf() function through the “%s” control string.

Also use the gets() and puts() functions.

Syntax:

Read Write

scanf(“%s”,array_name); printf(“%s”,array_name);

gets(array_name); puts(array_name);

Example:

char name[15];

printf(“Enter the name:”);

scanf(“%s”,name);

printf(“\nName:%s”,name);

OUTPUT:

Enter the name:Senthil

Name:Senthil

String Handling (or) Standard Functions:

The ‘C’ compiler provides the following string handling functions:

S.No. Function Purpose

1. strlen() Find length of the string

2. strcpy() Copy one string to another

3. strcat() Combine two strings

4. strcmp() Comparing two strings

5. strrev() Reverse a string

6. strlwr() Convert in to lower case

7. strupr() Convert into upper case

1. strlen():

This function is used to count & return the number of characters present in a string.

Syntax: int var=strlen(string1);

Example: char name[]=”Senthil”;

int len1,len2;

len1=strlen(name);

len2=strlen(“Kumar”);

printf(“%s length is %d”,name,len1);

printf(“\n%s length is %d”,”Kumar”,len1);

OUTPUT:

Senthil length is 7

Kumar length is 5

2. strcpy():

This function is used to copy the contents of one string to another .

Syntax: strcpy(string1,string2);

The contents of string2 copy to string1.

Example:

char str1[]=”Senthil”,str2[]=”Kumar”;

strcpy(str1,str2);

printf(“String1=%s\nString2=%s”,str1,str2);

OUTPUT:

String1=Kumar

String2=Kumar



3. strcat():

This function is used to concatenate (or) combine the two strings.

Syntax: strcat(string1,string2);

String2 is combined with string1

Example:

char str1[]=”Senthil”,str2[]=”Kumar”;

strcat(str1,str2);

printf(“The combined string:%s”,str1);

OUTPUT:

The combined string:SenthilKumar

4. strcmp():

This function is used to compares two strings and find out whether they are same or different.

The two strings are compared character by character until end of one string is reached.

When two strings are equal it will give value “Zero” otherwise give any other value.

Syntax: int var=strcmp(string1,string2);

Example:

char name1[]=”Kalai”,name2[]=”Malai”,name3[]=”Kalai”;

int I,j;

i=strcmp(name1,name2);

j=strcmp(name1,name3);

printf(“Comparison of %s & %s is %d”,name1,name2,i);

printf(“\nComparison of %s & %s is %d”,name1,name3,j);

OUTPUT:

Comparison of Kalai & Malai is 1

Comparison of Kalai & Kalai is 0

5. strrev():

This function is used to reverse a string.

Syntax: strrev(string1);

Example:

char str1[]=”Senthil”;

strrev(str1);

printf(“Reversed String=%s”,str1);

OUTPUT:

lihtneS

6. strlwr():

This function is used to converts the characters of string into lower case characters.

Syntax: strlwr(string1);

Example:

char str1[]=”SenThiL”;

strlwr(str1);

printf(“Converted lower case:%s”,str1);

OUTPUT:

Converted lower case:senthil

7. strupr():

This function is used to converts the characters of string into upper case characters.

Syntax: strupr(string1);

Example:

char str1[]=”SenThiL”;

strupr(str1);

printf(“Converted upper case:%s”,str1);

OUTPUT:

Converted upper case:SENTHIL

Sorting & Searching:

Sorting:

Arrange the elements either in ascending (or) descending order.

Elements are may be in the form of char, int, float values.



Descending order:

Bigger number is moved to top of all & smaller number is moved to bottom.

Ascending Order:

Smaller number is moved to top of all & bigger number is moved to bottom.

Types of Sorting:

1) Bubble sort

2) Insertion sort

3) Selection sort

4) Quick sort

1) Bubble sort:

It is the one of the easiest sorting method.

In this method each data item is compared with its neighbor.

It like as bubble near with another bubble so that it is called bubble sort.

Diagram:

Example:



//Bubble Sorting

#include<stdio.h>

#include<conio.h>

void main()

{

int a[]={35,75,45,5,25},j,i,temp=0;

clrscr();

printf("Bubble Sorting");

printf("\nUnsorted Elements:\n");

for(i=0;i<5;i++)

printf("%d\t",a[i]);

for(i=0;i<5;i++)

for(j=i+1;j<5;j++)

{

if(a[i]>a[j])

{

temp=a[i];

a[i]=a[j];

a[j]=temp;

}

}

printf("\nSorted Elements:\n");

for(i=0;i<5;i++)


getch();

}

OUTPUT:

Bubble Sorting

Unsorted Elements:

35 75 45 5 25

Sorted Elements:

5 25 35 45 75

Searching:

To determine if the particular data item is present in that collection.

Which data item to find is called the “key”.

Our task the key element matches in the collection of data items.

Types of Search:

1) Sequential (or) Linear search

2) Binary search

1) Sequential (or) Linear search:

It is the search the key element in sequentially.

That is search element matches check with element by element.

If the searching element is present in at last of the list means it will take more time.



Example:

//Linear or Sequential Search

#include<stdio.h>

#include<conio.h>

void main()

{

int a[]={4,21,36,14,62,5,10},key,i,t=0;

clrscr();

printf("Linear or Sequential Search");

printf("\nList of Elements:\n");

for(i=0;i<7;i++)


printf("\nEnter the search key:");

scanf("%d",&key);

for(i=0;i<7;i++)

{

if(a[i]==key)

{

t=1;

printf("\nThe %d is present in %d position",key,i+1);

break;

}

}

if(t==0)

printf("\nThe Element is not present\n");

getch();

}

OUTPUT:

Linear or Sequential Search

List of Elements:

4 21 36 14 62 5 10

Enter the search key:62

The 62 is present in 5 position

UNIT-4

FUNCTIONS:

A function is a set of instructions that are used to perform specified task.

Types of Functions:

i) User defined functions

ii) Built in functions

User Defined Functions:

The user defined functions has to be written by the programmer.

Built in functions:

These functions are not required to be written by the programmer.

Built in functions also called as pre defined (or) library functions.

Need for user defined function:

The program becomes too large & complex.

The users cannot go through at glance.

The task of debugging, testing & maintenance becomes difficult.

Elements of functions:

The functions contain following three elements:



1) Function declaration

2) Function Definition

3) Function calling

Example:

1) Function Declaration:

The function can be declared before they are defined.

The parameters must match.

Syntax:

Return_type function_name(Parameter list);

Return_type Datatype of the return value

Function_name Name of the function

Parameter list List of parameters

Example:



Int add(int x, int y); or void add();

2) Function Definition:

The function definition is the actual body of the function.

It is the process of specifying and establishing the operation.

Syntax:

Return_type function_name(parameter list)

{

Body of the function;

Return data;

}

3) Function call:

A function can be called by specifying its name, followed by a list of parameters.

The function definition may return a value to function call.

A semicolon (;) is used at the end of the statement.

Syntax:

Function_name(); (or) function_name(parameter);

Value=function_name(parameter);

Example:

Fun(); or fun(a,b);

C=fun(a,b);

Parameters:

Parameters provide the data communication between the function call & function definition.

Parameters are also called as arguments.

There are 2 types:

i) Actual parameters

ii) Formal parameters.

Actual and formal parameters must match.

i) Actual parameters: These parameters are present in the function call.

ii) Formal parameters: These are present in the function definition.

Example:

Void main()

{ void sum(int x, int y)

……. {

Body of the function;

…… }

Sum(a,b);

…..

……

}

Return Statement:

Value (or) information is returned from the function definition to the function call.

A function may contain more than one return statement.

Return type must be present in definition.

Syntax:

Return; (or) return(value (or) expression);

Example:

int first() int second()

{ {



….. ……

…. …

Return x*x; return a;

} }

Function prototypes:

The functions are classified into the following types depending on arguments present or not

and the value is returned or not.

These are called as function prototypes.

a) Function without arguments & no return values

b) Function with arguments & no return vales

c) Function with arguments & with return vales

d) Function without arguments & with return vales

a) Function without arguments & no return values:

Here, there is no data transfer between function call & function definition. i.e.,no

arguments

are passed

from main

function & no

value is

returned from

the sub

function.

Syntax:

Example:

void sum();

void main()

{

sum();

}

void sum()

{



int a,b,c;

printf("enter the two values:");


c=a+b;

printf("sum =%d",c);

}

Output:

enter the two values:10

20

sum =30

b) Function with arguments & no return values:

In this prototype, data is transferred from function call to the function definition.

The value does not return the function call so it is called one-way communication.

Syntax:

Example:

void sum(int,int);

void main()

{

int a,b;

printf("enter the two values:");


sum(a,b);

}

void sum(int x, int y)

{

int z;

z=x+y;

printf("sum=%d",z);

}

OUTPUT:

enter the two values:10

20



sum =30

c) Function with arguments & with return vales:

Here, the data is transferred between function call & function definition.

The value is returned to the function call. So it is called as two way communication.

Syntax:

Example:

void main()

{

int a,b,c;

clrscr();

printf(“enter the two values:”);


c=sum(a,b);

printf(“sum=%d”,c);

getch();

}


{

int z;

z=x+y;

return z;

}

Output:

Enter the values: 5 10

Sum=15

d) Function without arguments & with return values:

Here, no data is transferred between function call & function definition.

But the value is returned from the function definition to the function cal.

So it is called as one way communication.



Syntax:

Example:

void main()

{

int a,b,c;

clrscr();

c=sum();

printf(“sum=%d”,c);

getch();

}


{

int x,y,z;

printf(“enter the two values:”);

scanf(“%d%d”,&x,&y);

z=x+y;

return z;

}

OUTPUT:

Enter the values: 5 10

Sum=15

Parameter Passing Methods

There are 2 ways to pass a parameter inside the function. They are:

i) Call by Value

ii) Call by reference

i) Call by Value:

This method copies the values of actual parameters into the formal parameters of the

function.

The changes of the formal parameters cannot affect the actual parameters.

Because formal parameters are photocopy of the actual parameters.

Syntax:



void main()

{

…………

swap(a,b);

……….

}

swap(int a,int b)

{

int temp;

………….

}

Example:

void swap1(int,int);

void main()

{

int a=10,b=20;

clrscr();

printf("before swap: a=%d\t b=%d",a,b);

swap1(a,b);

printf("\nafter swap: a=%d\t b=%d",a,b);

}

void swap1(int x, int y)

{

int t;

t=x;

x=y;

y=t;

printf("\nIn function a=%d\t b=%d",x,y);

}

OUTPUT:

before swap: a=10 b=20

In function a=20 b=10

after swap: a=10 b=20

ii) Call by reference:

Call by reference is the addresses of actual parameters are copied into the formal parameters

inside the function.

The address is used to access the actual parameters inside the function also.

So, Changes made in parameters are permanent.

Here pointers are used to store the address.

Syntax:

void main()

{

…………..

swap(address of variable);

…………



}

void swap(pointer variable)

{

………..

}

Example:

void swap(int*,int*);

void main()

{

int a=10,b=20;

clrscr();

printf("before swap: a=%d\t b=%d",a,b);

swap(&a,&b);

printf("\nafter swap: a=%d\t b=%d",a,b);

}

void swap(int *x, int *y)

{

int t;

t=*x;

*x=*y;

*y=t;

}

OUTPUT:

before swap: a=10 b=20

after swap: a=20 b=10

Recursion:

Recursion takes the form of function that calls itself.

A process being performed where one of the instructions is to repeat the process.

It is similar to looping.

Recursion is the process of calling the same function itself again and again until some

condition is satisfied.

Syntax:

void function1();

{

---

---

function1();

}

The above function function1() is called themselves continuously.

Example:

void main()

{

int n,f;

printf("Enter the Number:");



scanf("%d",&n);

printf("\nThe factorial of %d = %d",n,fact(n));

}

int fact(int x)

{

int f;

if(x==1)

return 1;

else

f=x*fact(x-1);

return f;

}

OUTPUT:

Enter the Number:5

The factorial of 5 = 120

Tower of Hanoi:

The Tower of Hanoi is a mathematical game or puzzle.

It consists of three rods, and a number of disks of different

sizes which can slide onto any rod.

The puzzle starts with the disks in a neat stack in ascending

order of size on one rod, the smallest at the top, thus making a

conical shape.

The objective of the puzzle is to move the entire stack to another rod,

obeying the following simple rules:

1. Only one disk can be moved at a time.

2. Each move consists of taking the upper disk from one of the

stacks and placing it on top of another stack i.e. a disk can only

be moved if it is the uppermost disk on a stack.

3. No disk may be placed on top of a smaller disk.

http://en.wikipedia.org/wiki/Mathematical_game

http://en.wikipedia.org/wiki/Puzzle

http://en.wikipedia.org/wiki/Cone



With three disks, the puzzle can be solved in seven moves. The minimum number of moves

required to solve a Tower of Hanoi puzzle is 2n - 1, where n is the number of disks.

The Standard Library Functions

Some of the "commands" in C are not really "commands" at all but are functions.

For example, we have been using printf and scanf to do input and output, and we have used

rand to generate random numbers - all three are functions.

There are a great many standard functions that are included with C compilers and while these

are not really part of the language, in the sense that you can re-write them if you really want

to, most C programmers think of them as fixtures and fittings.

ASCII(American Standard Code for Information Interchange)

The most useful functions they contain follows:

S.No. Function Meaning Example OUTPUT

Mathematics functions

1. sqrt() It evaluates square root of x x=25; sqrt(x); 5

2. abs() The absolute value of integer quantity x=-75; abs(x); 75

3. pow(x,y) It evaluates the values of xy x=3,y=2; pow(x,y); 9

4. ceil() Round of given number. x=5.6;ceil(x); 6

Trigonometric Functions

5. sin() It evaluates sine value. x=30; sin(x); -0.99

6. cos() It evaluates cosine value. x=30; cos(x); 0.15

7. tan() It evaluates tangent value. x=30; tan(x); -6.41

Character Function

8. toascii() It gives ASCII value of the character. x=’a’; ascii(x); 97

9. tolower() It converts lowercase character. x=’A’; tolower(x); a

10. toupper() It converts uppercase character. x=’a’; toupper(x); A

Example:

#include<stdio.h>

#include<conio.h>

#include<math.h>

#include<ctype.h>

void main()

{

int x,y=2;

printf("\nEnter the number:");

scanf("%d",&x);

printf("\nThe squareroot of %d is %f",x,sqrt(x));

printf("\nThe value of %d power%dis%f ",x,y,pow(6,2));



printf("\nThe ceiling of 6.7 is %f",ceil(6.7));

printf("\nThe floor of 6.7 is %f",floor(6.7));

printf("\nThe absolute value of -6 is %d",abs(-6));

printf("\nThe value of sin 45 is %f",sin(45));

printf("\nThe uppercase of 'a' is %c",toupper('a'));

printf("\nThe uppercase of 97 is %c",toupper(97));

getch();

}

OUTPUT:

Enter the number:6

The squareroot of 6 is 2.449490

The value of 6 power 2 is 36.000000

The ceiling of 6.7 is 7.000000

The floor of 6.7 is 6.000000

The absolute value of -6 is 6

The value of sin 45 is 0.850904

The uppercase of 'a' is A

The uppercase of 97 is A

Pointers:

A pointer is a variable that is used to store the address of another variable.

It is declared like other variables and also it is always denoted by asterisk “*” operator.

Each variable has two attributes:

o Address

o Value

It can be used to access and manipulate data stored in the

memory.

Ordinary Variable:

int a=5;

aaccess the value

&a access the address of variable.

a variable

5 value

4002 address

Syntax: Data_type *pointer_variable;

Example: int *p;

Advantages:

1. It is increase the speed of execution.

2. It is saving memory space.

3. It enables us to access the memory directly.

4. It is also provide an alternate way to access an array.

5. Multiple data items can receive in the function.

Initializing pointer:

The process of assigning the address of a variable to a pointer variable is called initialization.

The location of the variable in system memory.

This can be achieved through the ampersand(&) symbol.

The ampersand(&) symbol is an address operator.



It takes the address of the variable.

Pointers must be initializing with assigning address of the variable.

Example:

void main()

{

int a=10,*p;

p=&a;

printf("\n*p=%d\tp=%d\t&p=%d\t&a=%d",*p,p,&p,&a);

}

OUTPUT:

*p=10 p=-12 &p=-14 &a=-12

*pvalue of the address stored in pointer variable.

Paddress of the variable.

&paddress of the pointer variable.

&aaddress of the variable.

a variable *p

10 value -12

-12 address -14

Pointer Arithmetic:

C pointer is an address, which is a numeric value.

Therefore, you can perform arithmetic operations on a pointer just as you can a numeric value.

There are four arithmetic operators that can be used on pointers: ++, --, +, and -

Data type Initial Address operation address after operation bytes of data type

char 4000 ++ 4001 1

char 4000 -- 3999 1

int 4000 ++ 4002 2

int 4000 -- 3998 2

float 4000 ++ 4004 4

float 4000 -- 3996 4

Incrementing a Pointer

Incrementing pointer is generally used in array.

The variable pointer to access each succeeding element of the array.

Incrementing pointer variable depends upon datatype of the pointer variable.

Example:

void main ()

{

int var[] = {10, 100, 200};

int i, *ptr;

ptr = var;

for ( i = 0; i < 3; i++)

{

printf("\nAddress of var[%d] = %u", i, ptr );

printf("\nValue of var[%d] = %d", i, *ptr );

ptr++;

}

}

OUTPUT:



Address of var[0] = 65520

Value of var[0] = 10





Decrementing a Pointer

The same considerations apply to decrementing a pointer, which decreases its value by the

number of bytes of its data type as shown below:

Example:

void main ()

{

int var[] = {10, 100, 200};

int i, *ptr;

ptr = &var[3-1];

for ( i = 3; i > 0; i--)

{

printf("Address of var[%d] = %u\n", i, ptr );

printf("Value of var[%d] = %d\n", i, *ptr );

ptr--;

}

}

OUTPUT:







Pointers and Arrays or Pointers and Functions:

• The elements of the array can also be accessed through a pointer.

• Pointers also send the array to functions.

Syntax:

Pointer_variable=array_name;

Example:

void fun(int[]);

void main()

{

int a[3]={10,20,30},*p;

p=a;

fun(p);

}

void fun(int b[])

{

int i,total=0;



for(i=0;i<3;i++)

total=total+b[i];

printf("\nTotal=%d",total);

}

OUTPUT:

Total=60

Unit-5

Structures and Union

Structures:

Structure is a compound datatype.

It stores different type of data items.

It is used to store dissimilar data items.

Structure is creating with the “struct” keyword.

It is the one of the storage unit.

Different type of data items can be store in different memory space.

The elements of structure are called members.

It must be declare and defined.

Structure Declaration and Definition:

It must be declare and defined.

Structure is creating with the “struct” keyword.

Structure finished declaration with semicolon(;).

Accessing members with dot(.) operator.

Syntax:

struct structure_name

{

Datatype variables;

----

};

Creating structure Variable:

struct structure_name structure_variable;

Structures

FLOAT INT

CHAR DOUBLE



Accessing structure Member:

structure_variable.member;

Difference between structure and array:

S.No. Array Structure

1. It is a collection of similar data items. it is collection of dissimilar data items

2. It is derived data type. It is a user defined data type.

3. It behaves like a built-in data types. It must be declared and defined.

4. An array can be increase or decrease. Its members can be added.

Example:

//Student Details using Structure

struct stud

{

int regno,m1,m2,m3,total;

char name[20],result[5];

};

void main()

{

struct stud s1,s2;

printf("\nStructures");

printf("\nEnter the Regno, Name:");

scanf("%d%s",&s1.regno,s1.name);

printf("\nEnter the Mark1, Mark2, Mark3:");

scanf("%d%d%d",&s1.m1,&s1.m2,&s1.m3);

s1.total=s1.m1+s1.m2+s1.m3;

if(s1.m1<50||s1.m2<50||s1.m3<50)

strcpy(s1.result,"Fail");

else

strcpy(s1.result,"Pass");

s2=s1; //Assigning structure

printf("Regno\tName\tMark1\tMark2\tMark3\tTotal\tResult\n");

printf("%d\t%s\t%d\t%d\t%d\t%d\t%s",s1.regno,s1.name,s1.m1,s1.m2,s1.m3,s1.total,s1.result);

printf("\nStructure--2");

printf("\nRegno\tName\tMark1\tMark2\tMark3\tTotal\tResult\n");

printf("%d\t%s\t%d\t%d\t%d\t%d\t%s",s2.regno,s2.name,s2.m1,s2.m2,s2.m3,s2.total,s2.result);

getch();

}

OUTPUT:

Enter the Regno, Name:345

kumar

Enter the Mark1, Mark2, Mark3:67

78

61

Regno Name Mark1 Mark2 Mark3 Total Result

345 kumar 67 78 61 206 Pass

Structure--2

Regno Name Mark1 Mark2 Mark3 Total Result

345 kumar 67 78 61 206 Pass

Structure within structure:

A structure can be declared within another structure.

It is also called nesting of structure.

The structure variables can be normal variable or pointer variable.



Nesting of more than one type of structure is allowed.

Structure cannot be nested within itself.

Syntax:

struct struct_1

{

----

----

};

struct struct_2

{

----

----

struct struct_1 s1;

};

Example:

// Structure within structure

struct college_detail

{

int college_id;

char college_name[20];

};

struct student_detail

{

int regno;

char name[20];

float percent;

struct college_detail c1;

};

void main()

{

struct student_detail s1={703,"kumar",87.3,1300,"XYZ college"};

printf("\nStructures within Structure\n");

printf("Regno\tName\tpercentage\tCollege ID\tCollege Name\n");

printf("%d\t%s\t%f\t%d\t%s",s1.regno,s1.name,s1.percent,s1.c1.college_id,s1.c1.college_name);

getch();

}

OUTPUT:

Structures within Structure

Regno Name percentage College ID College Name

703 kumar 87.300003 1300 XYZ college

Example:

//Employee Details using Structure

void dummy(float *a)

{

float b=*a; //perform some floating access

dummy (&b); //calling a floating point function

}

struct employee1

{

int empno;

char name[10];

float salary;

};



void main()

{

struct employee1 e[10];

int i,n;

printf("\nEnter the no.of Employees:");

scanf("%d",&n);

for(i=0;i<n;i++)

{

printf("\nEnter the employee empno,name,salary:");

scanf("%d%s%f",&e[i].empno,e[i].name,&e[i].salary);

}

printf("\nEmployee Details\n");

printf("\nEMPNO\tNAME\tSALARY");

for(i=0;i<n;i++)

printf("\n%d\t%s\t%.2f",e[i].empno,e[i].name,e[i].salary);

getch();

}

OUTPUT:

Enter the no.of Employees:2

Enter the employee empno,name,salary:23

Raj

5000


Kumar

3500

Employee Details

EMPNO NAME SALARY

23 Raj 5000.00

24 Kumar 3500.00

Union

• A Union is a collection of different data items, which are stored under a common name.

• Here same memory is shared by its members.

• The keyword union is used to define a union.

• Size of union is equal to the size of largest member.

• Memory allocated is shared by individual members of union.

• The address is same for all the members of a union.

• Altering the value of any of the member will alter other member values.

• Only one member can be accessed at a time.

• Only the first member of a union can be initialized.

Syntax: union union_name



{

union element1;

union element2;

…………………

};

Example: union result

{

int mark;

float avg;

char grade;

};

union result s;

Structure Union

1.The keyword struct is used to define a structure 1. The keyword union is used to define a union.

2. The size of structure is greater than or equal to the

sum of sizes of its members.

2. Size of union is equal to the size of largest

member.

3. Each member within a structure is assigned

unique storage area of location.

3. Memory allocated is shared by individual

members of union.

4. The address of each member will be in ascending

order.

4. The address is same for all the members of a

union.

5 Altering the value of a member will not affect

other members of the structure.

5. Altering the value of any of the member will

alter other member values.

6. Individual member can be accessed at a time 6. Only one member can be accessed at a time.

7. Several members of a structure can initialize at

once.

7. Only the first member of a union can be

initialized.

Example:

void dummy(float *a)

{

float b=*a; //perform some floating access

dummy (&b); //calling a floating point function

}

union employee1

{

int empno;

char name[10];

float salary;

};

void main()

{

union employee1 e[10];

int i,n;

printf("\nEnter the no.of Employees:");

scanf("%d",&n);

for(i=0;i<n;i++)

{

printf("\nEnter the employee empno,name,salary:");

scanf("%d%s%f",&e[i].empno,e[i].name,&e[i].salary);

}

printf("\nEmployee Details\n");

printf("\nEMPNO\tNAME\tSALARY");

for(i=0;i<n;i++)



printf("\n%d\t%s\t%.2f",e[i].empno,e[i].name,e[i].salary);

getch();

}

OUTPUT:

Enter the no.of Employees:2


Raj

5000


Kumar

3500

Employee Details

EMPNO NAME SALARY

16384 5000.00

-16384 3500.00

Preprocessor:

It is a program that processes the source program before compilation.

The C preprocessor executes before a program is compiled.

Preprocessor directives begin with # and only white-space characters and comments may

appear before a preprocessor directive on a line.

It operates under the following directives

1. File Inclusion

2. Macro substitution

3. Conditional inclusion

File Inclusion:

• It is used to include some file that contains functions or some definitions.

• Copy of a specified file included in place of the directive

Syntax:

#include<filename> Searches standard library for file

(or) #include“filename” Searches for user-defined files

Example:

#include<stdio.h>

#include<conio.h>

#include "addition.txt"

void main()

{

int a,b;

printf("\nEnter the numbers:");


printf("The Value is %d",add(a,b));

getch();

}

addition.txt

int add(int a,int b)

{

return(a+b);

}

OUTPUT:

Enter the numbers:7

4

The Value is 11



Macro Substitution:

• It is used to define and use integer, string, or identifier in the source program

• The three forms of macros are

– Simple Macro

– Argumented Macro

– Nested Macro

1) Simple Macro:

It is used to define some constants.

Syntax #define identifier string/integer

Example: #include<stdio.h>

#include<conio.h>

#define pi 3.14

#define CITY "chennai"

void main()

{

printf("The Value is %f",2*pi);

printf("\nThe Value CITY is %s",CITY);

getch();

}

OUTPUT: The Value is 6.280000

The Value CITY is chennai

2) Argumented Macro

• It is used to define some complex forms in the source program.

Syntax:

#define identifier (v1,v2,….) string/integer


#include<conio.h>

#define cube(n) (n*n*n)

void main()

{

printf("The Value of 3 cube is %d",cube(3));

getch();

}

OUTPUT: The Value of 3 cube is 27

3) Nested Macro

Here one macro is used by another macro.


#include<conio.h>

#define a 3

#define sq a*a

void main()

{

printf("The Value is %d",sq);

getch();

}

Output: The Value is 9



Conditional Inclusion:

It is used to include some conditional statements.

Example:

#include<stdio.h>

#include<conio.h>

#define a 3

#ifdef a

#define c a+5

#endif

void main()

{

printf("\nThe value C is %d",c);

getch();

}

Output:

The value C is 8

CP Notes

Documents

generation language

generation compute

generations of computer

micro computer

computer hardware

phase of computer

memory capacity

micro seconds