topic introduction

8/8/2019 Topic Introduction

1/63

OO

PProfessor: Aishy AmerCOEN243 Topic 01

Introduction to

Programming Methodology I

IntroductionOverview of Computers

ComputerHardware

ComputerSoftware

Programming Languages

Processing a Program

Software Development Method


2/63

OO

P

2

Introduction

OOP:

increasingly important both in academia and

industry

C++:

emerging as a language of choice

Because it combines

efficiency of C & the disciplined approachto software

design using interacting modules


3/63

OO

P

3

Introduction

COEN243: Object-Oriented Programming (OOP) with C++

Modular, general, maintainable programs Modular: classes and functions

General: can be applied formany applications/situations

Maintainable: a code thatthe maintainerunderstand

Focus: well-designed programs

meth

odologies

an

d con

cepts

following software engineering principles

C++ : very complex language be ready to workforlong hours


4/63

OO

P

4

Introduction

#include // Use the iostream library

using namespace std; // Use the standard library namespace

int main() // The mainroutine ofthe program

{

// *** Declaration/ Variables

float A,B,C,delta, root1,root2;

// *** Read input from user

cout > B >> C;

// *** Computation

delta = B*B - 4*A*C ;

root1 = -B/(2*A) + sqrt(delta)/(2*A);

root2 = -B/(2*A) - sqrt(delta)/(2*A);

// *** Outputresults

cout


5/63

OO

P

5

Introduction


6/63

OO

P

6

1.1 Overview of Computers

Computers/ Programs:

toolsto solve real-world problems

Programs are used to simulate the behaviorof

real-world systems

Simulation:

reproduction ofselected aspects ofthe system

behaviorthrough experimentations


7/63

OO

P

7

Overview of Computers

Very Large Scale Integration (VLSI)technology made computers affordable,smalland available to the public

Programming facilitatesthe use of computers

Programming has changed overtime:

Every few years a new programming language

Computer:

A device forcounting orcomputing

Two components: Hardware & Software


8/63

OO

P

8

1.2 ComputerHardware

Every computer is organized roughly into six

parts

CPU - central processing unit decisions are made

computations are performed

input/outputrequests are delegated

Main Memory

Stores information being processed by the CPU


9/63

OO

P

9

ComputerHardware

Secondary Memory

Stores data and programs

Input devices Allows people to supply informationto computers

Output devices

Allows people to receive information from computers

Networkconnection Modems/ Ethernet interface


10/63

OO

P

10

ComputerComponents


11/63

OO

P

11

Main Memory

Itstores

programs

data

results

Types of memory RAM

ROM


12/63

OO

P

12

Main Memory (2)-27.2

354

0.005

75.62

Address Content

0

1024

1

Memory:

an ordered sequence

ofstorage locationscalled memory cells

Every cell has a content

1023

RTV0001

108ADD1024

107

STR0005109


13/63

OO

P

13

Main Memory (3) To access cell info:

each cell has a unique address

Content may ormay not be meaningful to ourprogram

A cell =

A g rouping ofsmallerunits called bytes

A byte =

Amount ofstorage required to store a single

character

Numberof bytes percell varies


14/63

OO

P

14

Main Memory (4) A byte :

Composed ofsmallerunits ofstorage called bits

Binary:

a numbering system oftwo numbers 0 & 1

Bit = Binary digit:

Smallest element a computercan deal with

0 1 2 3 4 5 6 7

byte

a bit


15/63

OO

P

15

Main Memory (5) Assume a byte is composed of 1, 2,3, or8 bits

If 1 bit: it cantake 2 combinations

0 or

1 If 2 bits: it cantake 4 combinations

00 01 10 11

If 3 bits: 8 combinations

000 001 010 111

Often a byte = 8 bits

2^8=256 combinations orvalues


16/63

OO

P

16

Secondary Memory & Storage

Semi permanent data-storage capability

Tape orDisk Hard disk

CD ROM

Secondary memory has much more storagecapacity


17/63

OO

P

17

CPU

Brains ofthe computer

Arithmetic calculations are performed using theArithmetic/Logical Unit orALU

Control unit decodes and executes instructions

Arithmetic operations are performed usingbinary numbersystem


18/63

OO

P

18

CPU (2) Fundamental building blockis a switch

Switches are made from ultra-small transistors

Examples The Pentium processorcontains aboutthree

milliontransistors

The Pentium Pro has about 5.5 million

transistors


19/63

OO

P

19

Input/ Output Devices

Accessoriesthat allow computerto perform

specific tasks

Receiving information forprocessing Returnthe results of processing

Store information

Common input and output devices Printer Joystick CD-ROM

Keyboard Monitor


20/63

OO

P

20

ComputerNetworks

LAN - Local area network

Organizational

WAN - Wide area network

Internet

World Wide Web Introduced 1989

Developed by European Laboratory forParticle Physics


21/63

OO

P

21

1.3 ComputerSoftware

Applicationsoftware

Programs designed to perform specific tasksthat

are transparentto the user System software

Programsthatsupportthe execution and

development of otherprograms

Two majortypes

Operating systems

Translationsystems


22/63

OO

P

22

Application Software

Applicationsoftware has made using

computers indispensable and popular

Common applicationsoftware Word processors

Desktop publishing programs

Spreadsheets Presentation managers

Drawing programs


23/63

OO

P

23

Operating System (OS) Controls and managesthe computing resources

Importantservices of an OS

File system

Commands formanipulation ofthe file system

Perform input and output on a variety of devices

Management ofthe running systems

Examples Unix , Linux

MSDOS , Windows


24/63


25/63

OO

P

25

Programming Languages (2) Machine Language

Native tongue ofthe computer

Binary 0s and 1sthatspecify whatto do 0010 0000 0000 0100

1000 0000 0000 0101

0011 0000 0000 0110

High- Level Languages

Resemble human language (C++, C, Pascal) cost = price + tax;


26/63

OO

P

26

Programming Languages (3) Language Standard

Syntax (grammatical form) (rules) Portable

programs used without modification

Example:

if(tax >10)price= price * 3;else if(tax>5)price=price*2;


27/63

OO

P

27

Programming Languages (4) Source Program: tax.cc

Program you write

Object Program: tax.o Program translated from yourprogram

Executable Program: tax

Program translated from the object program


28/63

OO

P

28

Programming Languages (5) Programming paradigm:

design philosophy thathelpsto

thinkabout problems & formulate solutions

Examples:

imperative languages

structured languages

object-oriented languages


29/63

OO

P

29

Imperative Programming

A computer:

a large memory store

A program: a sequence of commandsstored inthe store

Emphasis onstored data

Examples: Assembly, Basic


30/63


31/63

OO

P

31

Structured Programming (2) Algorithms are the basis forthe functions

Highly structured

Top-down design Step-wise refinement

Abstraction:

Separation ofthe behaviorof a thing from itsrepresentation orimplementation


32/63

OO

P

32

Object Oriented Programming

(OOP) Real-world problemshave objects

Objects define the problem

OOP promotesthinking aboutsoftware in away that modelsthe real world

OOP supports good software engineering


33/63

OO

P

33

OOP (2) Emphasis is on

the objects (data) and

h

owto ma

nipula

te

them

A program:

A networkof objects withtheirattributes

Attributes = data and operations

There isnot one programming language best for

every type of problems


34/63

OO

P

34

Object Example

Real-world problem: Automated banking system

A BankAccount = a real object

Class BankAccount{

Data:

intnumber;

float balance;

Operations:deposit();

wihtdraw();

}


35/63

OO

P

35

OOP - Classes

A class:

A definition ofsomething

A class is an entity that definesthe attributesof an object

Attributes include data and operations

(methods)


36/63

OO

P

36

OOP Classes (2) Class:

an entity that definesthe attributes of an object

Object: An instance of a class

A bankAccount is a class

A particularbankaccount (yours) is an object


37/63

OO

P

37

Classes Hierarchy

Assume you wantto define a new classsimilar

to a predefined class

Example: Bank-Account

Saving Account

International Account


38/63

OO

P

38

Classes Hierarchy (2) The new class(sub class):

similarto the original class(superclass)

but with additional attributes Subclass inherits all attributes of a superclass

Classes are organized in a hierarchy

SuperClasses Sub Classes


39/63

OO

P

39

Classes Hierarchy Example

All kinds of accounts SuperClass

float balance;

Savings account only Sub Class floatrate;

Checking accounts only AnotherSub Class

float fee;


40/63

OO

P

40

OOP Class examples

classtime

{

private: hour, minute,second

public: setHour,setMinute, }

classstudent

{

private: name, address,ID, public: setName,setID,

}


41/63

OO

P

41

1.5 Object Oriented Design

Abstraction

Extractthe relevant properties of an object while

ignoring inessential details

Encapsulation

breaking down an object into parts

hiding and protecting its essential information

supplying an interface to modify the information

in a controlled and useful manner


42/63

OO

P

42

Object Oriented Design (2) Modularity

Dividing an object into smallerpieces ormodules

suchthatthe object is easierto understand and

manipulate

Hierarchy

Ranking orordering of objects based onsome

relationship betweenthem


43/63

OO

P

43

Abstraction

Process of extracting only the relevant

properties of an object Extracted properties define a view ofthe

object


44/63

OO

P

44

Abstraction (2) Cardealerviews a carfrom selling features

standpoint Price, warranty, color, etc.

Mechanic views a carfrom systems

maintenance standpoint Oil, oil filter,sparkplugs, etc.


45/63

OO

P

45

Encapsulation

Breaking down an object into parts,

hiding and protecting its essential information and

supplying an interface to modify the informationin a controlled and useful manner

By hiding the information itsrepresentation

and content can be changed without affecting

otherparts ofthe system


46/63

OO

P

46

Encapsulation (2) Example - carradio

Controlled by switches and knobs The details ofhow it works ishidden


47/63

OO

P

47

Modularity

Dividing an objectso thatthe objectholds

useful information and it is easierto

unde

rsta

nd

Most complex systems are modular

Cooling System

Ignition System

Fuel System


48/63

OO

P

48

Modularity (2) Example - Automobile can be decomposed

into subsystems

Cooling system Radiator

Thermostat

Waterpump

Ignitionsystem Battery

Starter

Sparkplugs


49/63

OO

P

49

Hierarchy

Ranking orordering of objects

based onsome relationship betweenthem Hierarchies facilitate understanding complex

organizations and systems

Example a company hierarchy helps employees understand the

structure oftheircompany and theirpositions


50/63

OO

P

50

1.6 Processing a High-Level

Language Program

Processing is a set of programs used to

develop software

A key component is a translator Types oftranslators

Compiler

Linker Examples

g++, Borland C++ , MS Visual C++


51/63

OO

P

51

Processing a Program (2) Editorused to enterthe program

Source program (file.cpp) UNIXnedittext editor

Compilertranslatesthe source program

Displayssyntax errors (not descriptive) Linker/Loaderto combine object file with

otherobject files

Executable program


52/63

OO

P

52

Processing a Program (3) Majoractivities

Editing

Compiling Linking with pre-compiled files

Object files

Library modules

Loading and executing

Viewing the behaviorofthe program


53/63

OO

P

53

Process

Cycle


54/63

OO

P

54

1.7 Software Development Method

Problem Analysis - (Correct Problem)Identify data objects

Goal to model properties Determine Input/ Output data

Constraints onthe problem

Design

Decompose into smallerproblems

Top-down design (divide and conquer) Develop Algorithm (Deskcheck)


55/63

OO

P

55

Software Development Method (2) Implementation

Writing the algorithm

Testing Verify the program meetsrequirements

System and Unittest

Documentation Key part inthe development process


56/63


57/63

OO

P

57

Software Engineering Goals

Reliability

An unreliable life-critical system can be fatal

Understandability Future development becomes very difficult if

software ishard to understand

Cost Effectiveness

Costto develop and maintainshould not exceed

profit


58/63

OO

P

58

Software Engineering Goals (2) Adaptability

System that is adaptive is easierto alterandexpand

Reusability

Improvesreliability and maintainability, and

reduces development costs

1 8 A l i th S ft


59/63

OO

P

59

1.8 Applying the Software

Development Method

Case Study: Converting Milesto Kilometers

Problem Yoursummersurveying job requiresto study some

mapsthat give distances inkilometers and some that

use miles

You and yourco-workers preferto deal in metricmeasurements

Write a program that performsthe necessary

conversion


60/63

A l i th S ft


61/63

OO

P

61

Applying the Software

Development Method

Design

The nextstep isto formulate the algorithm thatsolvesthe problem

Begin by listing the three majorsteps, orsub problems,ofthe algorithm

Implementation

To implementthe solution, you must write the

algorithm as a C++ program Testing

How do you know the sample run is correct?

1 9 P f i l Ethi


62/63

OO

P

62

1.9 Professional Ethics

for Programmers

Privacy and Misuse of Data

ComputerHacking Plagiarism and Software Piracy

Misuse of a ComputerResource


63/63

topic introduction

Documents