04 iec t1s1 oops session 05

8/14/2019 04 Iec t1s1 Oops Session 05

1/35

Slide 1 of 35Session 5Ver. 1.0

Object-Oriented Programming Using C#

In this session, you will learn to:Use static variables and static functionsIdentify the components of the .NET FrameworkUse the Visual Studio .NET IDE

Objectives


2/35



Static Variables and StaticFunctions

Each object has its own set of member variables.To retain the value of a variable throughout the program,you can declare the variable as a static variable.To manipulate and use the values of static variables, you

can define a function as static function.


3/35



Static Variables

The keyword ' static ' means that only one instance of agiven variable exists for a class.Static variables are used to define constants because their values can be retrieved by invoking the class without

creating an instance of it.Static variables can be initialized outside the member function or class definition.Unlike other member variables, only one copy of the staticvariable exists in the memory for all the objects of that class.


4/35



Static Functions

Static functions can access only static variables.Static functions exist even before the object is created.


5/35


Object-Oriented Programming Using C#Demo: Counting the Number of Times Function is Called by Using Static

Functions

Problem Statement:John a software developer in Zed Axsis Technology needs tocheck how many times a function is called. For the same, hehas been asked to create the function called CountFunction.Help John to create this function.


6/35



The .NET Framework, introduced by Microsoft, aims atintegrating various programming languages and services.The .NET Framework is designed to make significantimprovements in code reuse, code specialization, resource

management, multilanguage development, security,deployment, and administration.The .NET Framework consists of all the technologies thathelp in creating and running robust, scalable, anddistributed applications.

Introducing the .NET Framework


7/35Slide 7 of 35Session 5Ver. 1.0


The .NET suite consists of:.NET Products.NET Services.NET Framework

Let us understand each component of the .NET suite indetail.

Introducing the .NET Framework (Contd.)




.NET Products:.NET products aim at allowing developers to createapplications, which are capable of interacting seamlessly witheach other.All .NET products use eXtensible Markup Language (XML) for describing and exchanging data between applications.An example of a .NET product is Visual Studio .NET.





.NET Services:.NET helps you to create software as Web services. A WebService is an application or business logic that is accessiblethrough standard Internet protocols such as Hypertext Transfer Protocol (HTTP) and Simple Object Access Protocol (SOAP).You can identify the service by a Uniform Resource Locator (URL).Microsoft has come up with its own set of Web services, knownas My Services.This service allows users to access data by linking calendars,

phonebooks, address books, and personal references to thepassport authentication service.





The .NET Framework:It is the foundation for designing, developing, and deployingapplications.It is the core of the .NET infrastructure because it exists as alayer between the .NET applications and the underlyingoperating system.

Let us understand the .NET Framework in detail.





The various components of the .NET Framework are:Common Language RuntimeThe .NET Framework Class LibraryUser and Program Interfaces

Components of the .NET Framework




The following figure displays the various components of the .NET Framework.

Components of the .NET Framework (Contd.)

Common Language Runtime (CLR)

.NET Framework Class Libraries

WindowsForms

Web Forms andWeb Services

ConsoleApplications





Common Language Runtime (CLR):CLR is the environment where all programs in .NET areexecuted.CLR provides services such as code compilation, memoryallocation, and garbage collection.CLR allows the execution of code across different platforms bytranslating code into Intermediate Language (IL).IL is a low level language that the CLR understands.IL is converted into machine language during execution by theJIT compiler. During JIT compilation, code is also checked for

type safety.Type safety ensures that objects are always accessed in acompatible way.





CLR consists of a set of common rules followed by all thelanguages of the .NET Framework. This set of rules is knownas Common Language Specification (CLS).CLS enables an object or application to interact with theobjects or applications of other languages.

The classes that follow the rules specified by CLS are termedas CLS-compliant classes. The classes defined in the .NETFramework class library are CLS-compliant.One of the specifications defined in CLS is CTS, whichprovides a type system that is common across all languages.CTS define how data types are declared, used, and managedin the code at run time.While executing the program, CLR :

Identifies the process of compilationIdentifies the process of code execution





The .NET Framework Class Library:The .NET Framework class library works with any .NETlanguage, such as VB.NET, VC++ .NET, and VC#.The .NET Framework class library provides classes that canbe used in the code to accomplish a range of commonprogramming tasks, such as string management, datacollection, database connectivity, and file access.The .NET Framework class library comprises of:

NamespacesAssemblies





User and Program Interfaces:At the presentation layer, .NET provides three types of user interfaces:

Windows FormsWeb FormsConsole Applications

.NET provides a program interface, Web Services, tocommunicate with remote components.





Advantages of the .NET Framework:Consistent programming modelMulti-platform applicationsMulti-language integration

Automatic resource managementEase of deployment




Using Visual Studio .NET IDE

The Visual Studio .NET IDE provides you with a commoninterface for developing various kinds of projects for the.NET Framework. The IDE also provides you with a centralized location for designing the user interface for an application, writing code,and compiling and debugging the application .




Creating Projects and Solutions

In Visual Studio .NET, an application can be made up of one or more items, such as files and folders.To organize these items efficiently, Visual Studio .NET hasprovided two types of containers:

Project : It typically contains items that make up theapplication. These items are interrelated.Solution : It usually acts as a container for one or moreprojects.




Creating Projects and Solutions (Contd.)

The following figure shows a solution with multiple projects.

Solution

Project 1

Project 2

MiscellaneousFiles

Project 1Items

Project 2Items





To create a console application in Visual Studio, you needto create a project. To create a project, you need to performthe following steps:

1. Select Start All Programs Microsoft Visual Studio2005 Microsoft Visual Studio 2005 . TheStart Page - Microsoft Visual Studio window will bedisplayed.




2. Select File New Project . The New Project dialog box willbe displayed.





3. In the New Project dialog box, select Visual C# from theProject Types pane and Console Application from theTemplates pane.

4. Specify the name of the application in the Name text box. 5. Specify the location where the new project is to be created in

the Location combo box. You can use the Browse button tobrowse to the folder in which the new project is to be created.

6. Click the OK button.



24/35




User Interface Elements of Visual Studio .NET IDE:When you work with a console application project in VisualStudio .NET, you can use the following main elements inVisual Studio .NET IDE .


25/35



Standard Toolbar:The Standard toolbar is located below the menu bar. It providesshortcuts for menu commands.



26/35



Name Button Function

NewProject Creates a new project

Add New Item Add new item in the project

Save Saves the Program.

SaveAll Save all the unsaved itemsof the application

Cut Places selected text or objects on the WindowsClipboard

Copy Places a copy of selectedtext or objects on theWindows Clipboard

Paste Pastes the contents of theClipboard on the document.

Start Debugging Compiles and Executes thecurrent project.


The following table shows the various components of Standard toolbar.


27/35



The Start Page:When you start Visual Studio .NET, it displays theStart Page- Microsoft Visual Studio.The Start Page is the default home page for the browser providedwithin the Visual Studio .NET IDE.

This tab displays some of the recent projects and the last date of their modification. You can open any one of these projects.



28/35



The Solution Explorer Window:The Solution Explorer window lists the solution name, the projectname, and all the classes that are used in the project.



29/35



The Output Window:The Output window displays messages for the status of variousfeatures provided in the Visual Studio .NET IDE.



30/35



The Error List Window:The Error List window displays a list of errors along with thesource (the file and the line number) of the error. It helps youidentify and locate problems that are detected automatically asyou edit or compile code.



31/35



The Class View Window:The Class View window displays the classes, methods, andproperties associated with a particular file. They are displayed in ahierarchical tree-view depicting the containership of these items.



32/35



The Code Editor:The code editor allows you to enter and edit code. You may usethis editor to add code for your class.



33/35



To compile and execute the application, you need toperform the following steps:1. Select Build Build Solution or press F6 to compile the

application.2. Select Debug Start Debugging or press F5 to execute the

application.

Compiling and Executing Project


34/35



Summary

In this session, you learned that:The static variable retains its value even after the function towhich it belongs has been executed.The static functions can access only static variables.Non-static variables cannot be accessed by using staticfunctions. The .NET Framework is made up of many components, suchas Common Language Specification (CLS), Common languageRuntime (CLR), and Just-In-Time (JIT) compiler.CLS is a set of rules that are followed by all the languages of

the .NET Framework.When a program is compiled using Visual Studio .NET thecompiler translates the code into the Intermediate Language(IL) instead of machine language.


35/35


Summary (Contd.)

The Just-In-Time (JIT) compiler is used to translate code fromIL into machine language.The Common Language Runtime (CLR) is the environmentwhere all .NET applications are executed.The Visual Studio .NET Integrated Development Environment

(IDE) provides you with a common interface for developingvarious kinds of applications for the .NET Framework.Visual Studio .NET provides two types of containers, projectsand solutions to organize the constituents of an application.

04 iec t1s1 oops session 05

Documents