Programming 2 (CS-2300)

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Programming 2 (CS-2300)

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Different Programming Paradigms

⚫ Functional/procedural programming:

⚫ program is a list of instructions to the computer

⚫ Object-oriented programming

⚫ program is composed of a collection objects that

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History of Object-Oriented Programming

⚫ Started out for simulation of complex man-machine

systems, but was soon realized that it was suitable for all complex programming projects

⚫ SIMULA I (1962-65) and Simula 67 (1967) were the first two object-oriented languages

⚫ Developed at the Norwegian Computing Center, Oslo, Norway by Ole-Johan Dahl and Kristen Nygaard

⚫ Simula 67 introduced most of the key concepts of

object-oriented programming: objects and classes, subclasses (“inheritance”), virtual procedures

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The Ideas Spread

⚫ Alan Kay, Adele Goldberg and colleagues at Xerox PARC extend the ideas of Simula in developing Smalltalk

(1970’s)

⚫ Kay coins the term “object oriented”

⚫ Smalltalk is first fully object oriented language

⚫ Grasps that this is a new programming paradigm

⚫ Integration of graphical user interfaces and interactive program execution

⚫ Bjarne Stroustrup develops C++ (1980’s)

⚫ Brings object oriented concepts into the C programming language

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Other Object Oriented Languages

⚫ Eiffel (B. Meyer)

⚫ CLOS (D. Bobrow, G. Kiczales)

⚫ SELF (D. Ungar et al.)

⚫ Java (J. Gosling et al.)

⚫ BETA (B. Bruun-Kristensen, O. Lehrmann Madsen, B. Møller-Pedersen, K. Nygaard)

⚫ Other languages add object dialects, such as TurboPascal

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What is procedural Approach ?

⚫ In Procedural approach - code is organised(ﺔﻤﻈﻨﻤﻟا) into small "procedures (تاءاﺮﺟﻹا) that use and change the data.

⚫ Functions(تاءاﺮﺟﻹا) take some input.

⚫ Function Processes the input.

⚫ Function produce some output.

Shared Data

Function_1 Function_2 Function - 3

Output Output

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Object Oriented Programming ?

⚫ Data and Functions are grouped (ﻊﯿﻤﺠﺗ )together into class (ﺔﺌﻓ).

⚫ Class instantiates or creates (ﻖﻠﺧ)objects (مﺎﺴﺟﻷا).

⚫ the data inside an object can only be manipulated (ﺐﻋﻼﺘﻟا ) by calling the object's functions.

⚫ Data is locked( ﻞﻔﻘﻣ) inside object .

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Function 1

Function 2

Private Data

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Mapping the world to software

⚫

Objects in the problem domain are mapped to

objects in software

011101 10011 11101 0110100 11010 010101 1110101 10101

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⚫ Procedural Programming

⚫ Program is based(ﺪﻨﺘﺴﺗ) on

functions.

⚫ Importance (ﺔﯿﻤھأ) is not given to data but

Functions.

⚫ Top Down approach.

⚫ To add new data and

function in POP is not so easy.

⚫ No data hiding( ءﺎﻔﺧإ) – less secure. ⚫ Eg : C, VB, FORTRAN, Pascal. ⚫ Object Oriented Programming ⚫ program is based on objects. ⚫ Importance is given to

data not functions.

⚫ Bottom up approach.

⚫ An easy way to add new data and function.

⚫ Data is hidden – More security(ﻦﻣأ)

⚫ Example of OOP : C++, JAVA, VB.NET, C#.NET.

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Problem Description

⚫ “ …customers are allowed to have different types of bank accounts, deposit money, withdraw money and transfer

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Procedural Approach cont’d

⚫ Focus is on procedures

⚫ All data is shared: no protection

⚫ More difficult to modify

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Procedural Approach

bool MakeDeposit(int accountNum,float amount); float Withdraw(int accountNum,float amount);

struct Account { char *name; int accountNum; float balance; char accountType; };

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Procedural vs. Object-Oriented

⚫ Procedural

Withdraw, deposit, transfer

⚫ Object Oriented

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Object Oriented

⚫

Data and operations are grouped together

Account

Withdraw Deposit Transfer

Interface:

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Main OOPs Concepts

⚫ Object ⚫ Class ⚫ Encapsulation ⚫ Inheritance ⚫ Polymorphism

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Objects and Classes

⚫

Classes reflect concepts, objects reflect instances

that embody those concepts.

Daria Jane Brittany Jodie

girl

class

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Objects and Classes cont’d

⚫ A class captures(ﻂﻘﺘﻠﯾ) the common properties

(ﺔﻛﺮﺘﺸﻣ ﺺﺋﺎﺼﺧ) of the objects instantiated from it.

⚫ A class characterizes the common behavior (كﻮﻠﺴﻟا ﺔﻛﺮﺘﺸﻤﻟا) of all the objects that are its instances.

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Objects and Classes cont’d

Class BankAccount Balance InterestYTD Owner Account_number Balance 500 InterestYTD = 40 Owner = Sarah Ali Account_number = “1000101676” Balance 10,000 InterestYTD = 300 Owner = “Haya Dosairi” Account_number = “1000546564” Operations MakeDesposit Transfer WithDraw GetBalance

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Objects

⚫ Object are Instances of classes

⚫ It has

-identity – unique identification of an object -attributes – data/state

-services – methods/operations supported by the object

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Class : BOX (Identity) Int Length; Int Breadth; Int Height; Find_Area() Display_Area() Object : B1 Length = 5; Breadth = 4; Height =3; Object B2 Length = 7; Breadth = 6; Height =2; Attributes Methods Find_Area()

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Class

⚫ Class define the nature and properties (ﺺﺋﺎﺼﺧ) of objects

⚫ object is an instance of class

⚫ class groups similar objects

⚫ same (structure of) attributes

⚫ same services

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Objects as instances of Classes

⚫

The world conceptually(ﺔﯿﻤﯿھﺎﻔﻤﻟا ﺔﯿﺣﺎﻨﻟا ﻦﻣ) consists

of objects

⚫

Many objects can be said to be of the same type

or class

⚫ My bank account, your bank account, Bill ‘s bank account ,Diana’s Bank Account…

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Objects and Classes

⚫ Class

⚫ Visible in source code

⚫ The code is not duplicated

⚫ Object

⚫ Own copy of data

⚫ (ﺔﺻﺎﺨﻟا ﺔﺨﺴﻧ)

⚫ Active in running program

⚫ Occupies memory

⚫ Has the set of

operations given in the class

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Instantiation

⚫ An Object is instantiated from a Class

BankAccount myAccount;

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Data Encapsulation

class Account { private: float balance; public: float withdraw();

void deposit(float amount); );

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Advantages of Encapsulation

⚫ Protection

⚫ Consistency

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Inheritance

⚫ Inheritance is a form of software reusability where

⚫ New classes created from existing (دﻮﺟﻮﻣ )ones.

⚫ Subclasses absorb super-classes’ attributes and behaviors, and add in their own.

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Inheritance

⚫ A class which is a subtype of a more general class is said to be inherited from it.

⚫ The sub-class inherits the base class’s data members and member functions

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Inheritance cont’d

⚫ A sub-class has all data members of its base-class plus its own (ﺔﺻﺎﺨﻟا ءﺎﻀﻋﻷا)

⚫ A sub-class has all member functions of its base class (with changes) plus its own

⚫ Inheritance is meant to implement sub-typing (don’t abuse it)

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Example For Inheritance

Employee

Manager Programmer Trainee

Sr. Programmer Jr. Programmer Emp_n0,name,dob,qualif ication,address…… Dept_name,Proj_name,P roj_location Proj_code,Hrs,Incharge_ Detls Proj_code,Module_Code,( ةﺪﺣو ) Hours,Due_date

?

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Abstraction

⚫ Management of complexity

⚫ Hierarchical classification:

• is-a relationship: inheritance • has-a relationship: containment

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Encapsulation

⚫

Encapsulation facilitate us to understand and use a

data type without knowing all of its implementation

details

⚫

Separation between internal state of the object and its

external aspects

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Polymorphism

⚫ The word polymorphism means having many forms.(ﺪﯾﺪﻌﻟا لﺎﻜﺷأ ﻦﻣ).

⚫ A call to a member function will cause a different function to be executed depending on the type of object that

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An example for Polymorphism

Shape Area() Rectangle Area() Triangle Area()

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⚫ Polymorphism

⚫ Allows you to make the derived types behave differently from their base types.

⚫ It uses “late binding” instead of “early binding”

⚫ Example: Bird Move() Goose Move() Penguin Move()

Polymorphism

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Polymorphism

⚫ One interface

⚫ Multiple implementations

⚫ Inheritance

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Identify the classes and its attributes for

the following systems.

⚫ Hospital management System. – Eg:Patients

⚫ School Management System. - Eg: students

⚫ College Management System. – Eg:Students

⚫ Pharmacy Management System. – Eg: Medicine

⚫ Hotel Management System – Eg: Item

⚫ Student Examination system. – Eg: Exam_Marks

⚫ Supermarket System. - Eg : Items.

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Toys Sales System

Int Toy_code; Int Price; Int Description; Find_Price() Class : Toy Int Toy_code; Int Amount; Int Pur_Date; Find_Date_of_Purchase() Class : Purchase_Slip Int BillNo; Int Toy_code; Int Date; Find_Date_of_Bill () Class : Bill

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.NET – What Is It?

⚫ Software platform

⚫ Language neutral

⚫ In other words:

.NET is not a language (Runtime and a library for writing and executing written programs in any compliant language)

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What Is .NET

⚫ .Net is a new framework for developing web-based and windows-based applications within the Microsoft

environment.

⚫ The framework offers a fundamental shift in Microsoft strategy: it moves application development from

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.NET – What Is It?

Operating System + Hardware .NET Framework

.NET Application

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Base Class Library

Common Language Specification

Common Language Runtime ADO.NET: Data and XML VB VC++ VC#

Visual Studio.NET

ASP.NET: Web Services and Web Forms

JScript …

Windows Forms

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The .NET Framework

.NET Framework Services

⚫ Common Language Runtime

⚫ Windows® Forms

⚫ ASP.NET

⚫ Web Forms

⚫ Web Services

⚫ ADO.NET, evolution of ADO

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Compilation in .NET

Code in VB.NET Code in C# Code in another .NET Language

VB.NET compiler C# compiler Appropriate Compiler

IL(Intermediate Language) code

CLR just-in-time execution

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J2EE and .NET

Execution Engine J2EE

Java source code compiles into machine-independent byte code

Runtime Environment : JVM .NET

Any compliant language compiles into MSIL Runtime environment : CLR

Both JVM and CLR ,support services, such as code

verification, memory management via garbage collection, and code security

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J2EE and .NET

Language Support

J2EE

Tied to Java

Supports other languages via interface technology .NET

Language independent

Supports any language if mapping exists from that language to IL

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J2EE and .NET

Tools Support

J2EE

Can employ any number of tools

Pro :Developer has a great deal of choice

Con :Difficulty in choosing a right tool for a given job

.NET