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IT111P B55

Object Oriented

ProgrammingOOP and the programming industryPatrick Villar

8/26/2010

It shows how and what an OOP is; its usage, concepts features.

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Object Oriented Programming

OOP is simply including objects outside like sound files, image files, video files or user-defined

files to design applications and computer programs. Some of OOPs features or techniques are

Inheritance, Abstraction, Polymorphism and Encapsulation. Some if its basic concepts are Classes,

Objects, and Methods. OOP minimizes the fragmentation of codes making it easier to modify existingcodes and be used as objects instead. It helps the programmer to organize their own codes for

developing graphical user interface applications.

An advantage of OOP is at ease of modifying objects reducing the maintenance costs of the

system. OOP is also a complicated procedural programming but allows flexible interactions. According to

ArchWing Innovations OO systems are also easier for non-technical personnel to understand and easier

for them to participate in the maintenance and enhancement of a system because it appeals to natural

human cognition patterns.OOP can speed up developing time thus many objects are standard in some

systems and can be reused.

According to AWI there are almost two-dozen major OO languages, the leading commercial OO

languages are:

y C++y Smalltalky Java

C++

C++ is an OO version of C. It is compatible with C (it is actually a superset), so that existing C code can be

incorporated into C++ programs. C++ programs are fast and efficient.

Smalltalk

Smalltalk is a pure OO language. A rich class library and a dynamic development environment makes

Smalltalk a favorite of OO developers.

Java

Java is the latest, flashiest OO language. It has taken the software industry by storm due to its close ties

with the Internet and Web browsers. Java is a mixture of C++ and Smalltalk.

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OOP andC#

The new programming language C# is fully object-oriented and in many respects combines the

best elements of C++, Smalltalk, Java, and Visual Basic. C# is closest to Java among other programming

languages, and the basic structure of the .NET environment is rather close to the Java environment, with

C# and other .NET languages generating an intermediate language, which executes on a virtual machine(the Common Language Runtime). But C# contains some important enhancements. The most significant

is that in C# "everything is an object," as in Smalltalk. This uniformity greatly simplifies use of the

language, enabling numbers to be treated like objects, stored in collections, and so on. But whereas

Smalltalk paid a heavy performance penalty for such uniformity, C# has a unique concept of "boxing"

and "unboxing," in which a primitive value like a number can be "boxed" into an object wrapper when

there is need for the value to be treated as an object. But for usages where an object is not required,

simple values can be efficiently manipulated directly. http://zone.ni.com/

We can access an objects data and behaviour through and interface. The objects data and

behaviour is within the object so a program can treat it like a box accessible only through and interface.

Parts of an object

y Interfacey Behavioury Member or instance variablesThe code inside the method is a behaviour since it is the code that actually makes the object do the

work. Programs outside can use the object even if we change the implementation for as long as we

dont change the interface. As long as method name, parameter and returned value is unchanged, we

can alter the behaviour for as long as we want.

Classes inC#

[attributes] [modifiers] class identifier[:base-list] { class-body}[;]

Here are the parts of this statement:

y attributes (Optional)Attributes hold additional declarative information, as we'll see in Chapter14, "Using Attributes and Reflection."

y modifiers (Optional)The allowed modifiers are new, static, virtual, abstract, override, and avalid combination of the four access modifiers we'll see in this chapter.

y identifierThe class name.y base-list (Optional)A list that contains the base class and any implemented interfaces,

separated by commas.

y class-bodyDeclarations of the class members.

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Constructors

[attributes] [modifiers]identifier([formal-parameter-list])

[initializer] { constructor-body}

Here are the parts of this statement:

y attributes (Optional)Hold additional declarative information, as we'll see in Chapter 14.y modifiers (Optional)The allowed modifiers are new, static, virtual, abstract, override, and a

valid combination of the four access modifiers.

y identifierThe same as the class name.y formal-parameter-list (Optional)The optional parameters passed to the constructor. The

parameters must be as accessible as the constructor itself.

y initializer (Optional)Invoked before the execution of the constructor body. The initializer canbe one of the following with an optional argument-list:

:base (argument-list)

:this (argument-list)

y constructor-bodyThe block that contains the statements that initialize the object.Namespaces

namespacename[.name1] ...] {

type-declarations

}

Here are the parts of this statement:

y name, name1A namespace name can be any legal identifier, and it can include periods.y type-declarationsWithin a namespace, you can declare one or more of the following types:

another namespace, a class, interface, struct, enum, or delegate.

You can create as many namespaces in a file as you want; just enclose the code for each namespace in

the code block following the namespace keyword. For example, here's how we can put the Messager

class into the namespace Output:

namespace Output

{

classMessager

{

public string message = "Default message.";

public void DisplayMessage()

{

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System.Console.WriteLine(message);

}

}

}

To access Messager outside the Output namespace, you qualify its name as Output.Messsager, just as

you can qualify Console.Writeline as System. Console.WriteLine.

Some Examples

// private data, not publicly accessible

boolOnOff;

int volume;

int channel;

// accessor methods

SwitchOn() ;

SwitchOff() ;

SetVolume(int volume ) ;

SetChannel(int channel) ;

intGetVolume() ;

intGetChannel() ;

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Student Class Program

//Class

class Student

{

// Data Members

public string Name;

public int Age;

// Member Function

public void Display()

{

Console.WriteLine("Name {0}\n Age {1}", Name, Age);

}

}

//Main

using System;

namespace CSTutorials

{

class Student

{

// Data Members

public string Name;

public int Age;

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// Member Function

public void Display()

{

Console.WriteLine("Name {0}\n Age {1}", Name, Age);

}

}

class Program

{

static void Main(string[] args)

{

Student S1; // Declaration

S1 = new Student(); // Instantiation

Student S2 = new Student(); // Single line Declaration & Instantiation

// Assigning value to member variables

S1.Name = "Michael";

S1.Age = 37;

S1.Name = "Kimi";

S2.Age = 25;

// Invoking member function

S1.Display();

S2.Display();

Console.ReadLine();

}

}

}

Summary

Programming is made easier and efficient because of the OOPs concepts and features and

never ending improvement of the world of programming. More namespaces that we can include can

become or narrow down to small classes. Simply, OOP is used to make the programming industry

efficient in memory management and prevent the fragmentation of files used by users.

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Very useful references

http://www.archwing.com/technet/technet_OO.html

http://www.c-

sharpcorner.com/UploadFile/tusharkantagarwal/objectorientedcsharp11162005070743AM/obj

ectorientedcsharp.aspx

http://cplus.about.com/od/learnc/ss/csharpclasses.htm

http://www.informit.com/articles/article.aspx?p=101373&seqNum=2

http://zone.ni.com/devzone/cda/ph/p/id/45

http://www.astahost.com/info.php/Tutorial-Lesson-4-Object-Oriented-

Programming_t15397.html

http://www.google.com.ph/