GE6151

COMPUTER PROGRAMMING

GE6151 COMPUTER PROGRAMMING

UNIT I INTRODUCTION 8Generation and Classification of Computers- Basic Organization of a Computer –Number System –

Binary – Decimal – Conversion – Problems. Need for logical analysis and thinking – Algorithm –Pseudo code – Flow Chart.

UNIT II C PROGRAMMING BASICS 10Problem formulation – Problem Solving - Introduction to ‘ C’ programming –fundamentals –

structure of a ‘C’ program – compilation and linking processes – Constants, Variables – Data Types – Expressions using operators in ‘C’ – Managing Input and Output operations – Decision Making and Branching – Looping statements – solving simple scientific and statistical problems.

UNIT III ARRAYS AND STRINGS 9Arrays – Initialization – Declaration – One dimensional and Two dimensional arrays. String- String

operations – String Arrays. Simple programs- sorting- searching – matrix operations.

UNIT IV FUNCTIONS AND POINTERS 9Function – definition of function – Declaration of function – Pass by value – Pass by reference –

Recursion – Pointers - Definition – Initialization – Pointers arithmetic – Pointers and arrays- Example Problems.

UNIT V STRUCTURES AND UNIONS 9Introduction – need for structure data type – structure definition – Structure declaration – Structure

within a structure - Union - Programs using structures and Unions – Storage classes, Pre-processor directives.

UNIT I INTRODUCTION

Generation and Classification of Computers- Basic

Organization of a Computer –Number System – Binary –

Decimal – Conversion – Problems. Need for logical analysis

and thinking – Algorithm –Pseudo code – Flow Chart.

INTRODUCTION

INTRODUCTION

Early days people use fingers for computing purpose.

As years go, the computing needs also grew. This leads to the

invention of calculators and computers.

The term computer is derived from the word compute. The word

compute means to calculate

Definition A Computer is an electronic machine that accepts data from the user,

processes the data by performing calculations and operations on it,

and generates the desired output results.

Computer performs both simple and complex operations, with speed

and accuracy.

COMPUTERINPUT OUTPUT

Definition

1.”Computer is an electronic Device that is used for

performing calculations and controlling operations

that can be expressed either in logical or numerical

terms”.

2.”Computer is an electronic device which

automatically accepts and stores input data process

them and produce the desired result”.

3.“Computer may be defined as an electronic device,

that operates upon information or data”.

Basic functions or operationsInputProcessingOutputStoringControlling

Applications of computerBusiness IndustryHomeEducationPrinting & publishingEntertainment etc.,

CHARACTERISTICS OF COMPUTERSpeedAccuracyDiligenceVersatilityResource sharingStorage

CHAPTER 1

Generation and Classification of

Computers

Generations of Computers (Cont)

First Generation Computers:

These computers were vacuum tube based machines.

They used magnetic drums for memory.

Input were fed into the computer using Punched cards

The size of these computers were very large and it produce

more heat.

They lacked in versatility and speed.

They were more expensive.

Figure . Vacuum tube

Generations of Computers (Cont)Second Generation Computers

Here the Transistor replaced the bulky vacuum tubes.

Transistors are smaller than vacuum tubes and have

higher operating speed.

Thus the size of the computer got reduced considerably.

Manufacturing cost was also very low.

Fig. Transistors

Generations of Computers (Cont)

Third Generation Computers

These computers were based on Integrated Circuits (ICs) Technology.

A single IC has many transistors, registers and capacitors built on a

single thin slice of silicon.

So that the size of the computer got further reduced.

These Computers were small in size, low cost, large memory and

processing speed is very high.

Fig .IC CHIPS

Generations of Computers (Cont)Fourth Generation Computers

It uses large scale Integrated Circuits (LSIC) built on a single silicon

chip called microprocessors .

Later very large scale Integrated Circuits (VLSIC) replaced LSICs

These computers are called microcomputers.

Thus the size of the computer got reduced.

The personal computer (PC) are comes under the Fourth Generation.

Fig. Microprocessors

Generations of Computers (Cont)

Fifth Generation Computer

The speed is extremely high in fifth generation computer.

The concept of Artificial intelligence has been introduced to

allow the computer to take its own decision.

It is still in a developmental stage .

Classification of Computer

Classification of Computer •The digital computers that are available nowadays vary in their sizes

and types.

•The computers are broadly classified into four categories (Figure 1.8)

based on their size and type:

(1) Microcomputers

(2) Minicomputers

(3) Mainframe computers

(4) Supercomputer

Figure 1.8 . Classification of computers based on size and type

Slow Cheap Simple Small

Fast Expensive Complex Large

Microcomputer• Microcomputers are small, low cost and single-user digital computer

• consist of CPU,input unit, output unit, storage unit and the software.

• stand alone machines-can be connected together to create a network

Example:

• IBM PC based on Pentium microprocessor and Apple Macintosh

• Microcomputers include

desktop computers

notebook computers or laptop,

tablet computer

handheld computer

smart phones and netbook

PC

Figure 1.9 Microcomputers

Laptop

Smart phone

Netbook

Tablet PDA

Mini Computer

•This is designed to support more than one user at a time

•It possesses large storage capacity and operates at a higher speed

•This type of computer is generally used for processing large volume of

data in an organization.

Eg: Servers in Local Area Networks (LAN).

Mini computer

Mainframe Computers•They operate at very high speed, having very large storage capacity and

can handle the work load of many users

•They are generally used in centralized databases.

Mainframe computer

Supercomputers •They are the fastest and most expensive machines

•They have high processing speed compared to other computers

•They have also multiprocessing technique

• Supercomputers are mainly being used for whether forecasting,

biomedical research, Space Research and other areas of science and

technology

Supercomputer

CHAPTER2

BASIC ORGANISATION OF

COMPUTER

CONTROL

MEMORY

ALU

OUTPUTINPUT

Basic organization of computer

Basic organization of computer

INPUTThe input unit is used to information or instruction to the

computer.It accept the information or instruction from user or from

some where else.Convert it to a computer understandable form and send it to

the computer.

Eg:Keyboard,mouse,Joystick,MICR, etc,.

Basic organization of computer (cont)

CENTRAL PROCESSING UNIT (CPU)

It is the heart of the computer.

It performs all operations.

It contains the followingsCONTROL UNIT

ALU

MEMORY

Basic organization of computer (cont)

CONTROL UNIT

It controls all other units in the computer.

It directs the sequence in which operations to be performed.

It also controls the flow of data between various units.

Basic organization of computer (cont)

MEMORY UNIT

Place for holding the information.

Types

1.Primary

2.Secondary

Primary memory is used to store temporary data.

Eg:RAM,ROM etc,.

Secondary memory is used to store information permanently.

Eg:Hard disk.

Basic organization of computer

OUTPUT

The output unit is used to display the result of the process.

Eg:Monitor,printer,speakers, etc,.

CHAPTER 3

NUMBER SYSTEM

Data Representation

•The data stored in the computer may be of different kinds, as follows:

•Numeric data (0, 1, 2, ... , 9)

•Alphabetic data (A, B, C, ... , Z)

•Alphanumeric data-Combination of any of the symbols-(A, B, C ..

Z),

(0,1..9),or special characters (+,-, Blank), etc.

•All kinds of data, be it alphabets, numbers, symbols, sound data or video

data, is represented in terms of 0s and 1s, in the computer.

•Each symbol is represented as a unique combination of 0s and 1s.

Number system• A number system in base r or radix r uses unique symbols for r digits. One or

more digits are combined to get a number.

• base of the number decides the valid digits that are used to make a number.

• In a number, the position of digit starts from right-hand side of the number.

•Rightmost digit has position 0, the next digit on its left has position 1, and so

on.

•The digits of a number have two kinds of values:

• Face value• Position value

•The face value of a digit is the digit located at that position.

•For example, in decimal number 52, face value at position 0 is 2 and face value

at position 1 is 5.

•The position value of a digit is (base Position). For example, in decimal

number 52, the position value of digit 2 is 10° and the position value of digit 5

is 101. Decimal numbers have a base of 10.

•The number is calculated as the sum of, face value * base position, of each of

the digits

•For decimal number 52, the number is 5*101 + 2*10° = 50 + 2 = 52

•In computers, we concerned with four kinds of number systems, as follows:

• Decimal Number System -Base 10

• Binary Number System -Base 2

• Octal Number System - Base 8

• Hexadecimal Number System -Base 16

Number SystemNumber Base B => B symbols

Base 16 (Hexa) : 0, 1,……9, A ,…, E, F

Base 10 (Decimal) : 0, 1, 2,……, 7, 8, 9

Base 8(Octal) : 0, 1, 2, 3, 4, 5, 6, 7

Base 2 (Binary) : 0, 1

Number System (cont)

Number representation:

• d31d30 ... d2d1d0 is a 32 digit number

• value = d31x B31 + d30 x B30 + ... + d2 x B2 + d1 x B1 + d0

x B0

Decimal Numbers: Base 10

Base or Radix is 10

Digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Example:

41210 = 4x102 + 1x101 + 2x100

= 400 + 10 +2

= 412

Binary Numbers: Base 2

Base or Radix is 2

Digits: 0, 1

Example:

1012 = 1x22 + 0x21 + 1x20

= 4 + 0 +1

= 5

Octal Numbers: Base 8

Base or Radix is 8

Digits: 0, 1, 2, 3, 4, 5, 6, 7

Example:

1238 = 1x82 + 2x81 + 3x80

= 64 + 16 +3

= 83

Hexadecimal Numbers: Base 16

Digits: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F:

A 10

B 11

C 12

D 13

E 14

F 15

Example:

1216 = 1x161 + 2x160

= 16 +2

= 18

Conversions

Decimal to Base N Base N to Decimal

Successive Division by N(Remainder Method)

Multiplication with power of N

Decimal to Binary

Conversion of 2510 to Binary

2 252 12 -12 6 - 02 3 - 0

1 - 1

2510=110012

Binary to decimal conversion

11001 1X20 = 1 0X21 = 0 0X22 = 0 1X23 = 8 1X24 = 16

2510

Decimal to Octal

Conversion of 12510 to Octal

8 1258 15 - 5

1 - 7

12510=1758

Octal to decimal conversion

175 5X80 = 5 7X81 = 56 1X82 = 64

125

1758 = 12510

Conversion of 8410 to Octal8 848 10 - 4

1 - 2

8410=1248

Octal to decimal conversion

124 4X80 = 4 2X81 = 16 1X82 = 64

84

1248 = 8410

Decimal to Hexa

Conversion of 45010 to Hexadecimal

16 45016 28 - 2

1 - 12

45010=1C216

Hexa to decimal conversion

1C2 2X160 = 2 12X161 =

192 1X162 = 256

450

1C216 = 45010

Conversion of 38510 to Hexadecimal

16 38516 24 - 1

1 - 8

38510=18116

Hexa to decimal conversion

181 1X160 = 1 8X161 = 128 1X162 = 256

385

18116 = 38510

Other ConversionsBINARYOCTALBINARYHEXAOCTALHEXA etc,.

BINARYOCTALOCTAL – BASE 8 = 23

3 DIGIT BINARY NUMBERExample:110012 OCTAL 11 001

011 001 3 1 110012=318

Example:11100112 OCTAL

1 110 011

001 110 011 1 6 3

11100112=1638

BINARYHEXAHEXA – BASE 16 = 24

4 DIGIT BINARY NUMBERExample:110012 HEXA 1 1001

0001 1001 1 9 110012=1916

Example:11100112 OCTAL

1 110 011

001 110 011 1 6 3

11100112=1638

OCTALHEXAOCTALBINARYHEXAExample:318 HEXA

3 1 011 001

0001 1001 1 9318=1916

HEXA OCTALExample: 1BD OCTAL

1 B D0001 1011 1101

000 110 111 101 0 6 7 5

1BD = 6758

Conversion of 25.12510 to Binary

2 252 12 -12 6 - 02 3 - 0

1 - 1

2510=110012

0.125 X 2 = 0.2500.250 X 2 = 0.5 0.5 X 2 = 1.0

25.12510 = 11001.0012

Binary to decimal conversion11001.001 1X2-3 = 0.125 0X2-2 = 0 0X2-1 = 0 1X20 = 1 0X21 = 0 0X22 = 0 1X23 = 8 1X24 = 16 25.12510

Conversion of 84.25010 to Octal

8 848 10 - 4

1 - 2

8410=1248

0.250 X 8 = 2.000

25.12310 = 124.28

Octal to decimal conversion

124.2

2X8-1 = 0.25 4X80 = 1 2X81 = 0 1X82 = 0

25.25010

ASSIGNMENT

DECIMAL TO BINARY4379107241476

DECIMAL TO OCTAL391522847582534

DECIMAL TO HEXA75826312873594756

DECIMAL TO OTHER63 BASE4279 BASE6161 BASE7

BINARY OCTAL,HEXA1010101110101010111110101101111011110111101000101

OCTAL HEXA473123572457744625

75.12510 BASE2356.52310 OCTAL527.4210 HEXA

CHAPTER 4NEED FOR LOGICAL ANALYSIS AND

THINKING

NEED FOR LOGICAL ANALYSIS AND THINKING •Logical thinking is the process of understanding something; we put together

our judgment, reasoning, and other forms of thinking to reflect the reality of

knowledge.

•Logics and reasoning are also known as concepts of understanding something

logically.

•It is recognized as a structure of thinking and the analysis of the appearance

and development of something.

•Only through logical thinking, we can achieve the specific goals or targets.

•It is the advanced stage of understanding something, different thoughts may

apply on the same problem to get the specific task to be done.

•It is characterized by abstract, emotional, material, and analytical thinking.

•When finalizing the goal or target of something, we have put together our

judgment and reasoning, indirectly reflecting reality.

•Our brain is powerful in logical thinking, this enables us to scientifically

expose the essence of something in an abstract and logical way with our

consciousness.

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

ways of thinking are mainly induction, deduction, analysis and synthesis, from

abstract to the concrete.

•Logic is also known as abstract thinking, a higher form of thinking. Its

characteristics are abstract concepts, judgment and reasoning as basic forms of

thinking, such as analysis, synthesis, generalization, and so on. Thereby, it helps

to expose the essence of the characteristics and laws of the things that we

observe.

•The same logic applies to in computer programming.

ALGORITHM

ALGORITHM •Algorithm is an ordered sequence of finite, well defined, unambiguous

instructions for completing a task.

•Algorithm is an English-like representation of the logic which is used to

solve the problem.

•It is a step-by-step procedure for solving a task or a problem.

•The steps must be ordered, unambiguous and finite in number.

•For accomplishing a particular task, different algorithms can be written.

•The different algorithms differ in their requirements of time and space.

•The programmer selects the best-suited algorithm for the given task to be

solved.

•Let's now look at two simple algorithms to find the greatest among three

numbers, as follows:

Algorithm to find the greatest among three numbers:

ALGORITHM 1

Step 1: Start

Step 2: Read the three numbers A, B, C

Step 3: Compare A and B. If A is greater perform step 4 else perform step 5.

Step 4: Compare A and C. If A is greater, output "A is greatest" else output "C

is greatest". Perform step 6.

Step 5: Compare Band C. If B is greater, output "B is greatest" else output "C

is greatest".

Step 6: Stop

ALGORITHM 2

Step 7: Start

Step 8: Read the three numbers A, B, C

Step 9: Compare A and B. If A is greater, store A in MAX, else store B in MAX.

Step 10: Compare MAX and C. If MAX is greater, output "MAX is greatest"

else output "C is greatest".

Step 11: Stop

•Both the algorithms accomplish the same goal, but in different ways. The

programmer selects the algorithm based on the advantages and disadvantages of

each algorithm.

•For example, the first algorithm has more number of comparisons, whereas in

the second algorithm an additional variable MAX is required.

FLOWCHART

FLOWCHART• A flowchart is a diagrammatic representation of the logic for solving a

task.

• drawn using boxes of different shapes with lines connecting them to show

the flow of control.

• The purpose of drawing a flowchart is to make the logic of the program

clearer in a visual form.

•There is a famous saying "A photograph is equivalent to thousand

words". The same can be said of flowchart.

•The logic of the program is communicated in a much better way

•Since it is a diagrammatic representation-forms a common medium of

communication.

Flowchart Symbols

Sequence Selection

Control structures in flowchart

Examples of flowchart

1. The first flowchart computes the product of any two numbers and gives

the result. flowchart is a simple sequence of steps to be performed in a

sequential order.

2. The second flowchart compares three numbers and finds the maximum of

the three numbers. This flowchart uses selection. In this flowchart,

decision is taken based upon a condition, which decides the next path to

be followed, i.e. If A is greater than B the true (Yes) path is followed else

the false (No) path is followed. Another decision again made while

comparing MAX with C.

3. The third flowchart finds the sum of first 100 integers. Here, iteration

(loop) is formed so that some steps are executed repetitively until they

fulfill some condition exit from the repetition.

• In the decision box, the value of I is compared with 100. If false (No), a

loop is created which breaks when the condition becomes true (Yes).

• Flowcharts have their own benefits; however, they have some

limitations too.

• A com and long flowchart may run into multiple pages, which becomes

difficult to understand follow. Moreover, updating a flowchart with the

changing requirements is a challenging job.

PSEUDO CODE

Pseudo code •Pseudo code consists of short, readable and formally-styled English language

used for explaining an algorithm.

•Pseudo code does not include details like variable declarations, subroutines

•Pseudo code is a short-hand way of describing a computer program.

•Using pseudo code, it is easier for a programmer or a non-programmer to

understand the general working of the program, since it is not based on any

programming language.

•It is used to give a sketch of the structure of the program, before the actual

coding. It uses the structured constructs of the programming language but is

not machine readable•Pseudo code cannot be compiled or executed

Preparing a Pseudo Code 1.Pseudo code is written using structured English.

2.In a pseudo code, some terms are commonly used to represent the

various actions.

• Input (INPUT, GET, READ)

• output (OUTPUT, PRINT, DISPLAY)

• Calculations (COMPUTE, CALCULATE)

• incrementing (INCREMENT)

• ADD, SUBTRACT, INITIALIZE used for addition, subtraction, and

initialization, respectively.

3. Figure 2.5 shows the different pseudo code structures.

• The sequence structure is simply a sequence of steps to be executed in linear order.

• There are two main selection constructs

• if-statement

• case statement

• In the if-statement, if the condition is true then the THEN part is executed otherwise

the ELSE part is executed. There can be variations of the if-statement also, like

there may not be any ELSE part or there may be nested ifs.

• The case statement is used where there are a number of conditions to be checked. In

a case statement, depending on the value of the expression, one of the conditions is

true, for which the corresponding statements are executed. If no match for the

expression occurs, then the OTHERS option which is also the default option, is

executed.

Control structures for pseudo code

Examples of pseudo code

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