01 iec t1_s1_oo_ps_session_01

Object-Oriented Programming Using C#
Rationale

Object-oriented concepts form the base of all modern
programming languages. Understanding the basic concepts
of object-orientation helps a developer to use various
modern day programming languages, more effectively. C#
(C-Sharp) is an object-oriented programming language
developed by Microsoft that intends to be a simple, modern,
and general-purpose programming language for application
development.
The course is applicable to students who want to enter the
world of object-oriented programming, using the C#
language. This course provides a strong foundation in
object-oriented programming approaches and the
fundamentals of C# programming language.

Ver. 1.0 Session 1 Slide 1 of 45

Objectives

In this session, you will learn to:
Explain features of the object-oriented methodology
Describe the phases of the object-oriented methodology
Define classes in C#
Declare variables
Write and execute C# programs


Object-Oriented Methodology

Object orientation is a software development methodology
that is based on modeling a real-world system.
An object oriented program consists of classes and objects.

Let us understand the terms—class and objects


Object-Oriented Methodology (Contd.)

Class
Car

Suzuki Reno Toyota Camry Honda Acura

Objects


The Foundation of Object Orientation

An object means a ‘material thing’ that is capable of being
presented to the senses.
An object has the following characteristics:
It has a state
It may display behavior
It has a unique identity
Objects interact with other objects through messages.

Let us understand these concepts.


The Foundation of Object Orientation (Contd.)
Car positioned at one place defines it’s State

Movement of car defines it’s Behavior

Car number XX 4C 4546 shows
the Identity of the car


The Foundation of Object Orientation (Contd.)

Car is flashing the lights to pass
the message to the other car


Just a minute

Identify the possible states of the following objects:
1. A cell phone
2. A stereo

Solution:
1. States of a cell phone: Off, Ring, Vibrate, and Call
2. States of a stereo: Play, Pause, Rewind, and Forward


Just a minute

Dr. James and Mr. Hyde went to the railway station to book
tickets for 3rd December. At the railway station, they
requested the clerk at the ticket counter to book two tickets
for the Flying Express in the first class. Identify the
following:
1. The possible receiver of the message in this situation.
2. The possible method that the receiver can use.

Solution:
1. The receiver of the message in this case will be the clerk at
the ticket counter.
2. The clerk will check if two tickets are available on the
requested train in the desired class and for the desired date. If
the tickets are available, the clerk will enter the details (name,
age, departure date, and seat), confirm the reservation, and
collect the required fare.

Characteristics of the Object-Oriented Approach

Realistic modeling
Reusability
Resilience to change
Existence as different forms


Just a minute

State whether the following situations demonstrate
reusability:
1. Recycling paper
2. Pump reusability (same pump is used in a well and in a fuel
station)

Solution:
1. It does not represent reusability because the unusable paper
is destroyed before paper is recycled for use. The unusable
paper loses its identity and cannot be considered the same as
recycled paper.
2. It represents reusability because a pump can be used for
suction of water as well as petrol. It is not necessary to use
the same pump in both the cases. Two separate machines
can be used because both belong to the ‘Pump’ class.


Phases of Object Orientation

The following phases are involved in the software
development:
The Analysis phase
The Design phase
The Implementation phase

Let us discuss the process of constructing a building.


Just a minute

As a member of a team that is developing software for
DialCom Telecommunications, Inc., you have been
assigned the task of creating a software module that
accepts and displays customer details such as name, age,
and phone number. Identify the class that you will create
and the methods of the class.

Solution:
As per the problem statement, the class required is:
– Customer
The class should have the methods to:
Accept customer details
Display customer details


Introducing C#

A program is a set of instructions to perform a specific task.
Programming languages use programs to develop software
applications.
A compiler is a special program that processes the
statements written in a particular programming language
and converts them into a machine language.
This process of conversion is called compilation.


Introducing C# (Contd.)

C#, also known as C-Sharp, is a programming language
introduced by Microsoft.
C# is specially designed to work with the Microsoft’s .NET
platform.

Let us understand the structure of a C# program.


Classes in C#

Consider the following code example, which defines a class:
public class Hello
{
public static void Main(string[] args)
{
System.Console.WriteLine("Hello, World!
n");
}
}


Classes in C# (Contd.)

public class Hello The class Keyword
{ Is used to declare a
public static void class
Main(string[] args)
{
System.Console.WriteLine("He
llo, World! n");
}
}



public class Hello The class Name
{ Is used as an identifier
public static void for a class
Main(string[] args)
{
llo, World! n");
}
}



public class Hello The Main() Function
{ Is the entry point of an
public static void application
Main(string[] args)
Is used to create
{ objects and invoke
System.Console.WriteLine("He member functions
llo, World! n");
}
}



public class Hello System.Console.WriteLine()
{ Displays the enclosed text on
public static void the screen
Main(string[] args)
{

llo, World! n");
}
}



public class Hello The Escape Character
{ Displays New line
public static void character. Other special
Main(string[] args) characters can also be
{ displayed such as t, b
System.Console.WriteLine("He and r
llo, World! n");
}
}


Demo: Creating Classes

Problem Statement:
As a member of a team that is developing toys for JoyToys,
Inc., you have been assigned the task of creating a bike
module that accepts and displays bike details. Declare the Bike
class and its member functions. The member function that
accepts bike details should display the message “Accepting
Bike Details”. Similarly, the member function to display bike
details on the screen should display the message “Displaying
Bike Details”.


Declaring Variables

A variable is a location in the memory that has a name and
contains a value.
A variable is associated with a data type that defines the
type of data that can be stored in a variable.


Declaring and Initializing Variables

You can declare and initialize variables by using the
following syntax:
<data_type> <variable_name>=<value>;


Declaring and Initializing Variables (Contd.)

Consider the following Data Types in C#
example of declaring and Represents the kind of
initializing a variable:
data stored in a variable
int class_rank=2;
C# provides you with
various built-in data
types, such as:
• char
• int
• float
• double
• bool
• string


Data Types in C#

Let us now understand the various data types with the help
of examples.


Data Types in C# (Contd.)

string Name = “Peter”

float Marks = 83.56
int Age = 23
char Vowel = ‘a’


Data Types in C# (Contd.)

Consider the following Data types in C#
example of declaring and The following types of
initializing a variable: data types are supported
int class_rank=2; by C#:
• Value types

int Num;
Num
Num=5; 5

Memory allocated

Variable declared and Initialized

Memory Allocation in Value Type


Declaring and Initializing Variables

Consider the following Data types in C#
example of declaring and The following types of
initializing a variable: data types are supported
int class_rank=2; by C#:
• Reference types

string Str=“Hello”;

Address Str

H E L L O

0 1 2 3 4

Memory Allocation of the String Type Variable



Consider the following Naming variables in C#
example of declaring and The following rules are used
initializing a variable: for naming variables in C#:
int class_rank=2; • Must begin with a letter or
an underscore
• Should not contain any
embedded spaces or
symbols
• Must be unique
• Can have any number of
characters
• Keywords cannot be used
as variable names



Consider the following Examples and non-examples
example of declaring and of Naming Variables
initializing a variable:
Name
int class_rank=2;
#Score

Age

2Strank

Family_Size

Gender



Consider the Initializing Variables in C#
following example of Specifies the value that
declaring and needs to be stored in a
initializing a variable: variable. The value could be
int class_rank=2; an integer, a decimal, or a
character.


Accepting and Storing Values in Member Variables

To understand how to accept Console.ReadLine()
value in a variable, let us Is used to accept input
consider the following code from the user and store it
snippet: in the variable
int Number;
Number=
Convert.ToInt32(Console.Rea
dLine());


Accepting and Storing Values in Member Variables (Contd.)

To understand how to accept Convert.ToInt32()
value in a variable, let us Converts the value
consider the following code entered by the user to
snippet: the int data type
int Number;
Number=
Convert.ToInt32(Console.Rea
dLine());


Writing and Executing a C# Program

Let us know learn to write, compile, and execute a C#
program.


Creating a Sample C# Program

A C# program can be written by using an editor like
Notepad. Consider the following code, which declares a
class Car and also creates an object MyCar of the same
class: The using keyword is used to include
using System; the namespaces in the program.
class Car Comments are used to explain the
{ code and are represented by //
//Member variables symbols.
string Engine; Member variables are used to store
int NoOfWheels; the data for a class.
//Member functions Member functions are declared inside
void AcceptDetails() the class that are used to perform a
specific task.


Creating a Sample C# Program (Contd.)

{
Console.WriteLine("Enter the Engine Model");
Engine = Console.ReadLine();
Console.WriteLine("Enter the number of Wheels");
NoOfWheels = Convert.ToInt32(Console.ReadLine());
}
public void DisplayDetails()
{
Console.WriteLine("The Engine Model is:{0}",
Engine);
Console.WriteLine("The number of wheels are:{0}",
NoOfWheels);
}
}


Creating a Sample C# Program (Contd.)

//Class used to instantiate the Car class
class ExecuteClass The Execute class is used as a class from
{ where the Car class can be instantiated.
public static void Main(string[] args)
{
Car MyCar = new Car();
MyCar.AcceptDetails();
MyCar.DisplayDetails();
}
}


Compiling and Executing C# Program

After writing the program in a Notepad, you need to compile
and execute it to get the desired output.
The compiler converts the source code that you write into
the machine code, which the computer can understand.
The following steps are needed to compile and execute a
C# program.
1. Save the code written in the Notepad with an extension .cs.
2. To compile the code, you need to go to the Visual Studio
2005 Command Prompt window. Select StartAll
ProgramsMicrosoft Visual Studio 2005Visual Studio
ToolsVisual Studio 2005 Command Prompt. The Visual
Studio 2005 Command Prompt window is displayed to
compile the program.
3. In the Visual Studio 2005 Command Prompt window, move
to the location where the programs file is saved.


Compiling and Executing C# Program (Contd.)

4. Compile the program file by using the following command:
csc ExecuteClass.cs
5. To execute the code, type the following in the command
prompt:
ExecuteClass.exe


Demo: Creating a C# Program

Problem Statement:
David is the member of a team that is developing the
Automatic Ranking software for a tennis tournament. You have
been assigned the task of creating a program. The program
should accept the following details of a tennis player and
display it:
• Name, containing a maximum of 25 characters
• Rank as an integer
• Winning average as a decimal value
Help David to create the program.


Summary

In this session, you learned that:
According to the object-oriented approach, systems consist of
component objects that interact with each other.
An object is an entity that may have a physical boundary.
However, it should have the following characteristics:
• State
• Behavior
• Identity
– A class consists of a set of objects that share a common
structure and behavior.
– If an object desires an action from another object, it sends a
message to that object.
– The object that receives the message is called the receiver,
and the set of actions taken by the receiver constitutes the
method.


Summary (Contd.)

The features of the object-oriented approach are:
• Realistic modeling
• Reusability
• Resilience to change
• Existence as different forms
– A model of a system is built in the stages of analysis, design
and implementation.
– The purpose of the model is to help developers understand the
reality that they are trying to imitate.
– In C#, a class is created by using the keyword class. It is
identified by a name called the class name.
– The Console.WriteLine() method is used to display text on the
screen.
– Main() is the first function which is executed in a C# program.


Summary (Contd.)

Escape characters are used to display special characters such
as the newline character.
A variable is a named location in the memory, which contains a
specific value.
A datatype defines the type of data that can be stored in a
variable.
The two types of data type are Value type and Reference type.
The ReadLine() method is used to accept inputs from the
user.
The using keyword is used to include the namespaces in the
program.
A namespace contains a set of related classes.
Member variables are declared inside the class body.


Summary (Contd.)

Comment entries are notes written by a programmer in the
code so that others reading that code can understand it better.
An object is an instance of a class.
The compiler software translates a program written in a
language like C# into the machine language.


01 iec t1_s1_oo_ps_session_01

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

En vedette

En vedette (20)

Similaire à 01 iec t1_s1_oo_ps_session_01

Similaire à 01 iec t1_s1_oo_ps_session_01 (20)

Plus de Niit Care

Plus de Niit Care (20)

Dernier

Dernier (20)

01 iec t1_s1_oo_ps_session_01

Notes de l'éditeur