Computer Education

Php Projects

2010-09-03T04:52:00.000-07:00

As a php web developer, you should know that php is probably the language that has the biggest code repository. So no matter what module you want to include in your project there should be an open source solution.
This can help in various ways, but just in case you can’t think of one, here I put a few :

Open source is worked by many people, so the result is for sure better than one man’s work
You can have free updates to your code, while otherwise you should code the updates each time something new comes up
You save development time while your project is getting better

Anyway, after many years as a web developer, I’ve compiled a list of php classes that can be easily integrated in any project and I am regularly use.
Sending Emails
Sending emails is something very common for every web site. Php’s mail() function is good for this, but what if you want to attach a file, or send through an SMTP server, etc? Well in that case you should use phpmailer
User Manipulation
Another common module is the user module. With that you can manipulate users (login, logout, register, etc.) Personally I’ve never found a project that is good enough, so I created my own
Php user class is a module that can be used even in established projects, as it uses variable data for database tables, fields, session variables, etc.
Fetching RSS Feeds
Ever wanted to fetch an rss feed from your project? Well there is always an easy way to fetch a feed but in most cases you need more than that. When that is the case you should definitely use Magpie RSS
Geotargeting
There are many times that you need to know where are your visitors coming from. Maxmind gives a solution to this. For a complete tutorial check this article
Grabbing Remote Content
Some times RSS is not enough so you need to grab the content of a web page and parse it. If you are a huge fun of preg you should not continue reading, but if you are not you definitely need the htmlSQL class The htmlSQL class allow you to access html values with SQL code. Nice huh?
Trackback
Sending and receiving trackbacks is vital for a web site in our age. And in fact it is very easy if you are using a class like php trackback
Template System
Another thing that all sites use is a template. A template engine can save you lots of time, while it can make display changes very easy. A complete template engine that most projects use is Smarty
BBcode
BBcode used to be a functionality for forums, but as more and more sites use it in order to be more friendly to their users, you might want to use BBcode to your site. The problem is that BBcode requires a lot of coding and I am not sure if you have the time for this. If you don’t you’ll find StringParser_BBcode class very useful
Paypal Payment Integration
As you may know paypal has a nice API for developers who want to integrate paypal payments in their sites. The paypal IPN integration class helps you make use of it and start accepting payments in 20 minutes.
Editor Controls
I don’t have a problem to make changes to a site using phpMyAdmin or a simple text area, but when it comes to my clients I have to give them more than that. A javascript WYSIWYG editor is a perfect solution but as it requires countless hours to get it done I would suggest you to use the tinyMCE control
Hope you enjoyed this list. If I forgot something feel free to comment above

Php Manual

2010-09-02T07:06:00.000-07:00

Preface

PHP, which stands for "PHP: Hypertext Preprocessor" is a widely-used Open Source general-purpose scripting language that is especially suited for Web development and can be embedded into HTML. Its syntax draws upon C, Java, and Perl, and is easy to learn. The main goal of the language is to allow web developers to write dynamically generated web pages quickly, but you can do much more with PHP.

This manual consists primarily of a function reference, but also contains a language reference, explanations of some of PHP's major features, and other supplemental information.

You can download this manual in several formats at » http://www.php.net/download-docs.php. More information about how this manual is developed can be found in the 'About the manual' appendix. If you are interested in the history of PHP, visit the relevant appendix.

Authors and Contributors

We highlight the currently most active people on front page of the manual, but there are many more contributors who currently help in our work or have provided a great amount of help to the project in the past. There are a lot of unnamed people who help out with user notes on manual pages, which continually get included in the references, the work of whom we are also very thankful for. All of the lists provided below are in alphabetical order.

Authors and Editors

The following contributors should be recognized for the impact they have made and/or continue to make by adding content to the manual: Bill Abt, Jouni Ahto, Alexander Aulbach, Daniel Beckham, Stig Bakken, Nilgün Belma Bugüner, Jesus M. Castagnetto, Ron Chmara, Sean Coates, John Coggeshall, Simone Cortesi, Peter Cowburn, Daniel Egeberg, Markus Fischer, Wez Furlong, Sara Golemon, Rui Hirokawa, Brad House, Pierre-Alain Joye, Etienne Kneuss, Moriyoshi Koizumi, Rasmus Lerdorf, Andrew Lindeman, Stanislav Malyshev, Rafael Martinez, Rick McGuire, Kalle Sommer Nielsen, Yasuo Ohgaki, Richard Quadling, Derick Rethans, Rob Richards, Sander Roobol, Egon Schmid, Thomas Schoefbeck, Sascha Schumann, Dan Scott, Masahiro Takagi, Yannick Torres, Michael Wallner, Lars Torben Wilson, Jim Winstead, Jeroen van Wolffelaar and Andrei Zmievski.

The following contributors have done significant work editing the manual: Stig Bakken, Gabor Hojtsy, Hartmut Holzgraefe and Egon Schmid.

User Note Maintainers

The currently most active maintainers are: Daniel Brown, Nuno Lopes, Felipe Pena, Thiago Pojda and Maciek Sokolewicz.

These people have also put a lot of effort into managing user notes: Mehdi Achour, Daniel Beckham, Friedhelm Betz, Victor Boivie, Jesus M. Castagnetto, Nicolas Chaillan, Ron Chmara, Sean Coates, James Cox, Vincent Gevers, Sara Golemon, Zak Greant, Szabolcs Heilig, Oliver Hinckel, Hartmut Holzgraefe, Etienne Kneuss, Rasmus Lerdorf, Matthew Li, Andrew Lindeman, Aidan Lister, Hannes Magnusson, Maxim Maletsky, Bobby Matthis, James Moore, Philip Olson, Sebastian Picklum, Derick Rethans, Sander Roobol, Damien Seguy, Jason Sheets, Tom Sommer, Jani Taskinen, Yasuo Ohgaki, Jakub Vrana, Lars Torben Wilson, Jim Winstead, Jared Wyles and Jeroen van Wolffelaar.

Php Language

2010-08-31T22:37:00.000-07:00

I. What is PHP? * PHP is an open-source server-side scripting language (freely downloadable from php.net and zend.com). PHP version 5.2.14 is available on Webserve (www.indiana.edu, www.iupui.edu, www.iun.edu, and www.iuk.edu). * You can create dynamic web pages with the PHP scripting language. A dynamic Web page interacts with the user, so that each user visiting the page sees customized information. PHP can also be used to create dynamic web pages that are generated from information accessed from a MySQL database. * You can embed PHP commands within a standard HTML page. PHP's syntax is similar to that of C and Perl, making it easy to learn for anyone with basic programming skills. * Another feature that PHP offers is connectivity to most of the common databases. PHP also offers integration with various external libraries, which allow the developer to do anything from generating PDF documents to parsing XML. Return to Top II. Using PHP on Webserve 1. Bang lines are not required and will be ignored if present. (This information is provided for historical purposes as the previous web server environment required bang lines.) 2. You should use .php as the file extension. This refers to only PHP files executed directly via a URL. Include files may use other extensions, such as .inc. If you have PHP files that currently use .php4 extensions, it is strongly recommended that you move toward using .php for these instead. 3. The script must have owner execute permission. For best security, we strongly recommend using permissions set to 700 (only owner has read, write, and execute privileges). For example, where "script.php" is the name of the file containing the script, change the file permission as follows. chmod 700 script.php Return to Top III. Using Sessions in the Webserve Environment By default, when PHP creates a session file it stores it in /tmp. In the Webserve environment, however, you should create a session directory in the login of your account and write the session information there. You will need to do occasional cleanup of any unused session files in your account that aren't deleted. Doing it this way will guarantee session persistence and will prevent potential server issues as a result of filling up /tmp. The specifics of how writing session files to /tmp can impact session persistence in the Webserve environment is provided below. As indicated above, when PHP creates a session file, the default behavior is to store it in /tmp. The /tmp directory is local and independent to each of the backend web servers. Hence, if a request is made to server_1, it stores the session file in its own /tmp. If a subsequent request for the same user ends up going to server_2, it won't find the original session file. The load balancers control how web requests are distributed across the backend web servers. These load balancers are configured to provide session persistence by tracking the IP address of the web browser and the backend web server to which a request is sent. The goal is to send all subsequent requests from a given web browser back to the same backend web server. As a result, normally the PHP session files in /tmp work as expected because the multiple requests for the same user is consistently sent to the same backend web server. However, the load balancers can only cache so much data and eventually older data is overwritten by new incoming requests. This can cause the loss of persistence information. Since PHP allows you to specify the location of the session files (i.e., other than /tmp) you should be sure to create a session directory in the login of your account and write session information there. Doing this will require you to periodically do cleanup of unused session files that are not deleted. Return to Top IV. Troubleshooting When running your scripts, if you receive a 500 Internal Server Error message, please check the following: 1. Check to make sure the file permission is set to 700 (read, write, and execute for owner only). 2. Check the Directory (folder) permission. Setting it to 777 will give you a 500 - Internal Server Error. Set it to 711. 3. When the file/directory permissions are set correctly, and you are still getting a 500 error, it is likely due to line compatibility between the program used to create/upload the file and the Linux server. To correct this, login to the account on Webserve via an SSH client that provides a command line interface and do the following: 1. Move to the directory where your php file is using the 'cd' command (e.g., cd www). 2. Open the file using an editor such as nano and save it by typing Ctrl + o This simple steps may solve your problem because it converts Windows CR/LF (carriage return/line feed) to Unix LF (line feed) or Mac CR to Unix LF. To prevent this problem, you need to change settings/preferences in the program you are using to develop php files. To set preferences in Dreamweaver, go to Edit => Preferences. Select Code Format or HTML Format (depending on the versions). Change Line Breaks to LF (Unix). Return to Top V. Sample PHP Code Place a file containing the code below inside the www directory of your Webserve account and save it as info.php To view the file, you would then provide the web site address to the file. For example: http://www.indiana.edu/~myaccount/info.php It will output information about the current state of PHP, which includes information about PHP compilation options and extensions, the PHP version, server information and environment (if compiled as a module), the PHP environment, OS version information, paths, master and local values of configuration options, HTTP headers, and the PHP License. Because every system is setup differently, phpinfo() can be used to check configuration settings and for available predefined variables on a given system . For more information see php.net's entry for phpinfo. Return to Top VI. Increasing the Memory Limit You can increase the memory limit with a php.ini file in the same directory as your php script. If you have multiple subdirectories, you will need to place the php.ini file in each subdirectory that has php scripts. In that php.ini file you can specify the memory_limit you wish to set by using: memory_limit = whatever integer you wish You can verify the memory_limit has changed by creating a php info file.

Asp.net Interview Questions

2010-08-28T22:05:00.000-07:00

#61607; .NET

- Difference between asp and asp.net
- How do you do exception management
- If you are using components in your application, how can you handle exceptions raised in a component
- Can we throw exception from catch block
- How do you relate an aspx page with its code behind page
- What are the types of assemblies and where can u store them and how
- What is difference between value and reference types
- Is array reference type / value type
- Is string reference type / value type
- What is web.config. How many web.config files can be allowed to use in an application
- What is differnce between machine.config and web.config
- What is shared and private assembly
- What are asynchronous callbacks
- How to write unmanaged code and how to identify whether the code is managed / unmanaged.
- How to authenticate users using web.config
- What is strong name and which tool is used for this
- What is gacutil.exe. Where do we store assemblies
- Should sn.exe be used before gacutil.exe
- What does assemblyinfo.cs file consists of
- What is boxing and unboxing
- Types of authentications in ASP.NET
- difference between Trace and Debug
- Difference between Dataset and DataReader
- What is custom tag in web.config
- How do you define authentication in web.Config
- What is sequence of code in retrieving data from database
- About DTS package
- What provider ADO.net use by default
- Where does web.config info stored? Will this be stored in the registry?
- How do you register the dotnet component or assembly?
- Difference between asp and asp.net
- Whis is stateless asp or asp.net?
- Authentication mechanism in dotnet
- State management in asp.net
- Types of values mode can hold session state in web.config
- About WebService
- What are Http handler
- What is view state and how this can be done and was this there in asp?
- Types of optimization and name a few and how do u do?
- About DataAdapters
- Features of a dataset
- How do you do role based security
- Difference between Response.Expires and Expires.Absolute
- Types of object in asp
- About duration in caching technique
- Types of configuration files and ther differences
- Difference between ADO and ADO.net
- About Postback
- If you are calling three SPs from a window application how do u check for the performance of the SPS

.NET Architecture

2010-08-24T08:16:00.000-07:00

Most applications need data access at one point of time making it a crucial component when working with applications. Data access is making the application interact with a database, where all the data is stored. Different applications have different requirements for database access. VB .NET uses ADO .NET (Active X Data Object) as it's data access and manipulation protocol which also enables us to work with data on the Internet. Let's take a look why ADO .NET came into picture replacing ADO.

Evolution of ADO.NET

The first data access model, DAO (data access model) was created for local databases with the built-in Jet engine which had performance and functionality issues. Next came RDO (Remote Data Object) and ADO (Active Data Object) which were designed for Client Server architectures but, soon ADO took over RDO. ADO was a good architecture but as the language changes so is the technology. With ADO, all the data is contained in a recordset object which had problems when implemented on the network and penetrating firewalls. ADO was a connected data access, which means that when a connection to the database is established the connection remains open until the application is closed. Leaving the connection open for the lifetime of the application raises concerns about database security and network traffic. Also, as databases are becoming increasingly important and as they are serving more people, a connected data access model makes us think about its productivity. For example, an application with connected data access may do well when connected to two clients, the same may do poorly when connected to 10 and might be unusable when connected to 100 or more. Also, open database connections use system resources to a maximum extent making the system performance less effective.

Why ADO.NET?

To cope up with some of the problems mentioned above, ADO .NET came into existence. ADO .NET addresses the above mentioned problems by maintaining a disconnected database access model which means, when an application interacts with the database, the connection is opened to serve the request of the application and is closed as soon as the request is completed. Likewise, if a database is Updated, the connection is opened long enough to complete the Update operation and is closed. By keeping connections open for only a minimum period of time, ADO .NET conserves system resources and provides maximum security for databases and also has less impact on system performance. Also, ADO .NET when interacting with the database uses XML and converts all the data into XML format for database related operations making them more efficient.

The ADO.NET Data Architecture

Data Access in ADO.NET relies on two components: DataSet and Data Provider.

DataSet

The dataset is a disconnected, in-memory representation of data. It can be considered as a local copy of the relevant portions of the database. The DataSet is persisted in memory and the data in it can be manipulated and updated independent of the database. When the use of this DataSet is finished, changes can be made back to the central database for updating. The data in DataSet can be loaded from any valid data source like Microsoft SQL server database, an Oracle database or from a Microsoft Access database.

Data Provider

The Data Provider is responsible for providing and maintaining the connection to the database. A DataProvider is a set of related components that work together to provide data in an efficient and performance driven manner. The .NET Framework currently comes with two DataProviders: the SQL Data Provider which is designed only to work with Microsoft's SQL Server 7.0 or later and the OleDb DataProvider which allows us to connect to other types of databases like Access and Oracle. Each DataProvider consists of the following component classes:

The Connection object which provides a connection to the database
The Command object which is used to execute a command
The DataReader object which provides a forward-only, read only, connected recordset
The DataAdapter object which populates a disconnected DataSet with data and performs update

Data access with ADO.NET can be summarized as follows:

A connection object establishes the connection for the application with the database. The command object provides direct execution of the command to the database. If the command returns more than a single value, the command object returns a DataReader to provide the data. Alternatively, the DataAdapter can be used to fill the Dataset object. The database can be updated using the command object or the DataAdapter.

Component classes that make up the Data Providers

The Connection Object

The Connection object creates the connection to the database. Microsoft Visual Studio .NET provides two types of Connection classes: the SqlConnection object, which is designed specifically to connect to Microsoft SQL Server 7.0 or later, and the OleDbConnection object, which can provide connections to a wide range of database types like Microsoft Access and Oracle. The Connection object contains all of the information required to open a connection to the database.

The Command Object

The Command object is represented by two corresponding classes: SqlCommand and OleDbCommand. Command objects are used to execute commands to a database across a data connection. The Command objects can be used to execute stored procedures on the database, SQL commands, or return complete tables directly. Command objects provide three methods that are used to execute commands on the database:

ExecuteNonQuery: Executes commands that have no return values such as INSERT, UPDATE or DELETE
ExecuteScalar: Returns a single value from a database query
ExecuteReader: Returns a result set by way of a DataReader object

The DataReader Object

The DataReader object provides a forward-only, read-only, connected stream recordset from a database. Unlike other components of the Data Provider, DataReader objects cannot be directly instantiated. Rather, the DataReader is returned as the result of the Command object's ExecuteReader method. The SqlCommand.ExecuteReader method returns a SqlDataReader object, and the OleDbCommand.ExecuteReader method returns an OleDbDataReader object. The DataReader can provide rows of data directly to application logic when you do not need to keep the data cached in memory. Because only one row is in memory at a time, the DataReader provides the lowest overhead in terms of system performance but requires the exclusive use of an open Connection object for the lifetime of the DataReader.

The DataAdapter Object

The DataAdapter is the class at the core of ADO .NET's disconnected data access. It is essentially the middleman facilitating all communication between the database and a DataSet. The DataAdapter is used either to fill a DataTable or DataSet with data from the database with it's Fill method. After the memory-resident data has been manipulated, the DataAdapter can commit the changes to the database by calling the Update method. The DataAdapter provides four properties that represent database commands:

SelectCommand
InsertCommand
DeleteCommand
UpdateCommand

When the Update method is called, changes in the DataSet are copied back to the database and the appropriate InsertCommand, DeleteCommand, or UpdateCommand is executed.

.Net Uses

2010-08-23T06:31:00.000-07:00

cPanel is the industry leader for turning standalone servers into a fully automated point-and-click hosting platform. Tedious tasks are replaced by web interfaces and API-based calls. cPanel is designed with multiple levels of administration including admin, reseller, end user, and email-based interfaces. These multiple levels provide security, ease of use, and flexibility for everyone from the server administrator to the email account user.

cPanel is an organization that wins the loyalty of customers around the world by providing feature-rich applications backed by a team of developers, technical support engineers and quality assurance experts that provide stable builds, direct support, and fantastic customer service.

cPanel powers web hosting companies and organizations that have a need to automate and offer competitive hosting services.

cPanel Direct Licensing

cPanel can be installed on any server worldwide. If you currently operate your own servers and wish to purchase the cPanel software directly, it can be purchased online at the cPanel Store. Every direct software purchase receives priority support, installation support, and migration assistance.

.NET Framework and Languages

2010-08-20T06:55:00.000-07:00

As mentioned on the .NET Framework page, .NET Framework is designed for cross-language compatibility.
Cross-language compatibility means .NET components can interact with each other irrespective of the languages they are written in. An application written in VB .NET can reference a DLL file written in C# or a C# application can refer to a resource written in VC++, etc. This language interoperability extends to Object-Oriented inheritance.

This cross-language compatibility is possible due to common language runtime. As you read on the .NET Framework page, when the .NET program is compiled, the output of the compiler is not an executable file but a file that contains a special type of code called the Microsoft Intermediate Language (MSIL). This MSIL is a
low-level language which is designed to be read and understood by the common language runtime. Because all .NET executables exist as IL, they can freely operate. The Common Language Specification defines the minimum standards that .NET language compliers must confirm to. Thus, any code compiled by a .NET complier can interoperate with the .NET Framework.

The Common Type System (CTS) defines the rules concerning data types and ensures that code is executed in a safe environment. Since all .NET applications are converted to IL before execution all primitive data types are represented as .NET types. This means that, a VB Integer and a C# int are both represented in IL code as System.Int32. Because both the languages use a common and interconvertible type system, it is possible to transfer data between components and avoid time-consuming conversions.

Languages supported by .NET Framework

The table below lists all the languages supported by the .NET Framework and describes those languages. The languages listed below are supported by the .NET Framework upto the year 2003. In future there may be other languages that the .NET Framework might support.

.NET Frame Work Description

2010-08-19T07:59:00.000-07:00

Many ISV's, enterprises and Microsoft product teams are successfully building on the new features Windows Workflow Foundation (WF), Windows Communication Foundation (WCF), Windows Presentation Foundation (WPF) and Windows CardSpace in the .NET Framework 3.0.

Microsoft plans to continue to invest in the .NET Framework developer platform and in support of existing users the .NET Framework 3.5 has a minimal number of breaking changes. So that existing applications built for .NET Framework 2.0 or .NET Framework 3.0 should continue to run without requiring changes.

The .NET Framework 3.5 adds new features in several major technology areas; including:
· Deep integration of Language Integrated Query (LINQ) and data awareness
· ASP.NET AJAX for quickly creating more efficient, more interactive and highly-personalized Web experiences that work across all the most popular browsers
· New web protocol support for building WCF services including AJAX, JSON, REST, POX, RSS, ATOM and several new WS-* standards
· Full tooling support for WF, WCF and WPF including the new workflow-enabled services technology
· New classes in the base class library (BCL) for the .NET Framework 3.5 address the most common customer requests.

.NET Framework 3.5 is planned to release at the end of 2007 and will ship with Visual Studio code name "Orcas" and will also continue to be available for separate download from MSDN.

The Microsoft .NET Framework 3.0 (which is formerly known as WinFX), is the new managed code programming model for Windows. It combines the power of the .NET Framework 2.0 with new technologies for building applications that have visually compelling user experiences, seamless communication across technology boundaries, and the ability to support a wide range of business processes.

These new technologies are Windows Presentation Foundation, Windows Communication Foundation, Windows Workflow Foundation, and Windows CardSpace (formerly code named "Infocard"). Microsoft plans to ship .NET Framework 3.0 as part of the Windows Vista operating system. In addition, Microsoft is making these technologies available on Windows XP and Windows Server 2003.

.NET Framework 3.0 can be installed on any of the following systems:
· Microsoft Windows 2003 Server Service Pack 1 (SP1)
· Windows XP SP2
· Windows Vista
Windows Vista comes with .NET Framework 3.0. There is no separate installation package required. The standalone .NET Framework 3.0 packages are not supported on Vista.

Requirements:

Processor
Minimum:
· 400 megahertz (MHz) Pentium processor

Recommended:
· 1 gigahertz (GHz) Pentium processor

RAM
Minimum:
· 96 megabytes (MB)

Recommended:
· 256 MB

Hard Disk: Up to 500 MB of available space may be required.

Display
Minimum:
· 800 x 600, 256 colors

Recommended:
· 1024 x 768 high color, 32-bit

Microsoft Connected Services Framework 3.0 Service Pack 1 Enterprise Edition

Microsoft Connected Services Framework is an integrated, server-based packaged software product for building and managing services by using a service-oriented architecture (SOA). For telecommunications operators and other service providers, CSF enables them to aggregate, provision, and manages converged communications services for their subscribers across multiple networks and a range of device types.

Microsoft Connected Services Framework 3.0 Service Pack 1 (SP1) addresses many of the high priority requests from our customers including a dramatic improvement in the setup and configuration of the CSF components. CSF 3.0 SP1 also includes support for WCF-based services, which includes WS-reliable messaging and better performance. Can be downloaded from Connected Services Framework 3.0 EE SP1

Requirements of Microsoft Connected Services Framework 3.0 Service Pack 1 Enterprise Edition:

· Internal Information Services 6.0
· Active Directory (Functional Level 2000)
· Microsoft .NET Framework 2.0
· Microsoft SQL Server 2000 Service Pack 4 (SP4), or 2005 SP1
· Windows Support Tools 2003 SP2
· Microsoft Operations Manager 2005 SP1
· UDDI 2.0
· Enterprise Single Sign-On 3.0
· Microsoft Clusting Server (if clustering is required)
· Microsoft Management Console 3.0
· Web Service Enhancement 3.0

Microsoft .NET Framework 3.0 Service Pack 1 Language Packs contain translated text, such as error messages, for languages other than English. Without the installation of a Language Pack, these messages are displayed in English by default.

Multiple language packs, each for a different language, can be installed on a single computer. Microsoft .NET Framework 3.0 SP1 Language Packs contain translated text, such as error messages, for each language.

The following Language Packs are designed for NET Framework 3.0 SP1 x86 ONLY : French , Greek , Spanish , Italian , German , Japanese.

The following Language Packs are designed for NET Framework 3.0 SP1 x64 ONLY : French , Spanish , Italian , German , Japanese.

.NET Framework 3.0 Service Pack 2 Update for Windows Server 2003 and Windows XP

There are some known incompatibilities in generic types using the BinaryFormatter or NetDataContractSerializer serialized and deserialized across a mixed .NET Framework 3.5 SP1 and .NET Framework 4 environment. Installing this update addresses these issues.

Microsoft .NET Framework 3.5 Service pack 1 Beta

Microsoft .NET Framework 3.5 service pack 1 is a cumulative update that contains many new features building incrementally upon .NET Framework 2.0, 3.0, 3.5, and includes .NET Framework 2.0 service pack 2 and .NET Framework 3.0 service pack 2 cumulative updates.

.NET Framework version 3.5 Service Pack 1 provides the following new features and improvements:

· ASP.NET Dynamic Data, which provides a rich scaffolding framework that allows rapid data driven development without writing code, and a new addition to ASP.NET AJAX that provides support for managing browser history (back button support). For more information, see What's New in ASP.NET and Web Development.

· Core improvements to the common language runtime that include better layout of .NET Framework native images, opting out of strong-name verification for fully trusted assemblies, improved application startup performance, better generated code that improves end-to-end application execution time, and opting managed code to run in ASLR (Address Space Layout Randomization) mode if supported by the operating system. Additionally, managed applications that are opened from network shares have the same behavior as native applications by running with full trust.

· Performance improvements to Windows Presentation Foundation, including a faster startup time and improved performance for Bitmap effects. Additional functionality for WPF includes better support for line of business applications, native splash screen support, DirectX pixel shader support, and the new WebBrowser control.

· ClickOnce application publishers can decide to opt out of signing and hashing as appropriate for their scenarios, developers can programmatically install ClickOnce applications that display a customized branding, and ClickOnce error dialog boxes support links to application-specific support sites on the Web.

· The Entity Framework is an evolution of the existing suite of ADO.NET data access technologies. The Entity Framework allows developers to program against relational databases in terms of application-specific domain models instead of the underlying database models. For more information see Getting Started with the Entity Framework. The Entity Framework introduces some additional features, including support for new SQL Server 2008 types, default graph serialization of Entities, and the first broad public release of the Entity Data Source. With this release, the Entity Framework supports the new date and file stream capabilities in SQL Server 2008. The graph serialization work helps developers who want to build Windows Communication Foundation (WCF) services that model full graphs as data contracts. The Entity Data Source provides a traditional data source experience for ASP.NET application builders who want to work with the Entity Framework.

· LINQ to SQL includes new support for the new date and file stream capabilities in SQL Server 2008.

· The ADO.NET Data Services Framework consists of a combination of patterns and libraries, which enable data to be exposed as a flexible REST (Representational State Transfer)-based data service that can be consumed by Web clients within a corporate network or across the Internet. The ADO.NET Data Services Framework makes data service creation over any data source. A conceptual view model of the underlying storage schema can easily be exposed through rich integration with the ADO.NET Entity Framework. Services created using the ADO.NET Data Services Framework, as well as compatible Windows Live (dev.live.com) services, can be easily accessed from any platform. For client applications running on Microsoft platforms, a set of client libraries are provided to make interaction with data services simple. For example, .NET Framework-based clients can use LINQ to query data services and a simple .NET Framework object layer to update data in the service.

· Windows Communication Foundation now makes the DataContract Serializer easier to use by providing improved interoperability support, enhancing the debugging experience in partial trust scenarios, and extending syndication protocol support for wider usage in Web 2.0 applications.

· The .NET Framework Data Provider for SQL Server (SqlClient) adds new support for file stream and sparse column capabilities in SQL Server 2008.

IMPORTANT: This beta release is for early testing and feedback. As a beta release, we recommend you only install the service pack on test computers. Prior to installation, you should carefully review the included readme file to be aware of any known issues with this release. For example, this service pack has some known compatibility issues with previous releases, including:
· Expression Blend (all versions)
· Silverlight 2 Beta 1 SDK
· Silverlight Tools Beta 1 for Visual Studio 2008

.NET And Its Importance

2010-08-18T08:15:00.000-07:00

In the world of computers, software plays very important role just as hardware. This was recognized by Microsoft in earlier stages. Looking for new ways to improve their software, Microsoft made its software efficient not only to users but to developers as well.

.Net architecture not only helps businesses to make their existing software assets powerful but also to add new software services making them more productive. It can also prove effective in reducing application complexity and the related costs of developing and maintaining software.

.Net application development has helped to simplify development and customize of various enterprise level applications. This product comes as a part of Microsoft's Windows Operating System. .Net framework comes bundled with a lot of advantages, which makes it a widely used tool for .Net application development.

The .Net is built on the following Internet standards:

-UDDI, standard to search and discover Web Services
-XML, format for exchanging data between Internet Applications
-HTTP, communication protocol between Internet Applications
-SOAP, standard format for requesting Web Services

Advantages of .Net Software Development Services:

-Easy integration of any software into the Internet
-Supports directory services that can answer XML based questions
-Permits a wide variety of Internet devices to access data and applications
-Supports different levels of authentication of services such as passwords, wallets, and smart cards
-Ability to track visitors and report on the most requested web pages

The .Net framework is a set of huge library that encompasses various programming needs like user interface design, web development, data access, database connections, networking among many other algorithms. Hence the advent of .Net programming has simplified and made .Net application development very extensive.

Let's look at some important features of .Net framework:

-No language dependency
-Enhanced Security
-Easy deployment
-Easy Portability
-Interoperability

Commercial .Net Services that can be provided to Businesses:

- .Net Software Product Development
- .Net Desktop and Web Application Development
- Web Services based .Net Application development
- .Net custom control development
-.Net system design and application development
- .Net Architecture and design evaluation
- Developing web services using the .Net framework and the SOAP toolkit
- Migrating web and desktop applications to .Net
- Migration of application from .Net

.Net helps to develop your business, by generating large volumes of data that contain valuable information like individual facts about their customers, products, operations and people. By using .Net technology, web software outsourcing helps your business to do better.

Java Interview Questions

2010-08-14T21:44:00.000-07:00

What is meant by pass by reference and pass by value in Java?

Pass by reference means, passing the address itself rather than passing the value. Pass by value means passing a copy of the value.

If you’re overriding the method equals() of an object, which other method you might also consider?

hashCode()

What is Byte Code?

What gives java it’s “write once and run anywhere” nature?

All Java programs are compiled into class files that contain bytecodes. These byte codes can be run in any platform and hence java is said to be platform independent.

Expain the reason for each keyword of public static void main(String args[])?

public- main(..) is the first method called by java environment when a program is executed so it has to accessible from java environment. Hence the access specifier has to be public.

static: Java environment should be able to call this method without creating an instance of the class , so this method must be declared as static.

void: main does not return anything so the return type must be void

The argument String indicates the argument type which is given at the command line and arg is an array for string given during command line.

What are the differences between == and .equals() ?

what is difference between == and equals

Difference between == and equals method

What would you use to compare two String variables - the operator == or the method equals()?

How is it possible for two String objects with identical values not to be equal under the == operator?

The == operator compares two objects to determine if they are the same object in memory i.e. present in the same memory location. It is possible for two String objects to have the same value, but located in different areas of memory.

== compares references while .equals compares contents. The method public boolean equals(Object obj) is provided by the Object class and can be overridden. The default implementation returns true only if the object is compared with itself, which is equivalent to the equality operator == being used to compare aliases to the object. String, BitSet, Date, and File override the equals() method. For two String objects, value equality means that they contain the same character sequence. For the Wrapper classes, value equality means that the primitive values are equal.

 public class EqualsTest {

 public static void main(String[] args) {

  String s1 = “abc”;
  String s2 = s1;
  String s5 = “abc”;
  String s3 = new String(”abc”);
  String s4 = new String(”abc”);
  System.out.println(”== comparison : ” + (s1 == s5));
  System.out.println(”== comparison : ” + (s1 == s2));
  System.out.println(”Using equals method : ” + s1.equals(s2));
  System.out.println(”== comparison : ” + s3 == s4);
  System.out.println(”Using equals method : ” + s3.equals(s4));
 }
}

Output
== comparison : true
== comparison : true
Using equals method : true
false
Using equals method : true

What if the static modifier is removed from the signature of the main method?

What if I do not provide the String array as the argument to the method?

Program compiles. But at runtime throws an error “NoSuchMethodError”.

Why oracle Type 4 driver is named as oracle thin driver?

Oracle provides a Type 4 JDBC driver, referred to as the Oracle “thin” driver. This driver includes its own implementation of a TCP/IP version of Oracle’s Net8 written entirely in Java, so it is platform independent, can be downloaded to a browser at runtime, and does not require any Oracle software on the client side. This driver requires a TCP/IP listener on the server side, and the client connection string uses the TCP/IP port address, not the TNSNAMES entry for the database name.

What is the difference between final, finally and finalize? What do you understand by the java final keyword?

What is final, finalize() and finally?

What is finalize() method?

What is the difference between final, finally and finalize?

What does it mean that a class or member is final?

o final - declare constant
o finally - handles exception
o finalize - helps in garbage collection

Variables defined in an interface are implicitly final. A final class can’t be extended i.e., final class may not be subclassed. This is done for security reasons with basic classes like String and Integer. It also allows the compiler to make some optimizations, and makes thread safety a little easier to achieve. A final method can’t be overridden when its class is inherited. You can’t change value of a final variable (is a constant). finalize() method is used just before an object is destroyed and garbage collected. finally, a key word used in exception handling and will be executed whether or not an exception is thrown. For example, closing of open connections is done in the finally method.

What is the Java API?

The Java API is a large collection of ready-made software components that provide many useful capabilities, such as graphical user interface (GUI) widgets.

What is the GregorianCalendar class?

The GregorianCalendar provides support for traditional Western calendars.

What is the ResourceBundle class?

The ResourceBundle class is used to store locale-specific resources that can be loaded by a program to tailor the program’s appearance to the particular locale in which it is being run.

Why there are no global variables in Java?

Global variables are globally accessible. Java does not support globally accessible variables due to following reasons:

The global variables breaks the referential transparency
Global variables creates collisions in namespace.

How to convert String to Number in java program?

The valueOf() function of Integer class is is used to convert string to Number. Here is the code example:
String numString = “1000″;
int id=Integer.valueOf(numString).intValue();

What is the SimpleTimeZone class?

The SimpleTimeZone class provides support for a Gregorian calendar.

What is the difference between a while statement and a do statement?

A while statement (pre test) checks at the beginning of a loop to see whether the next loop iteration should occur. A do while statement (post test) checks at the end of a loop to see whether the next iteration of a loop should occur. The do statement will always execute the loop body at least once.

What is the Locale class?

The Locale class is used to tailor a program output to the conventions of a particular geographic, political, or cultural region.

Describe the principles of OOPS.

There are three main principals of oops which are called Polymorphism, Inheritance and Encapsulation.

Explain the Inheritance principle.

Inheritance is the process by which one object acquires the properties of another object. Inheritance allows well-tested procedures to be reused and enables changes to make once and have effect in all relevant places

What is implicit casting?

Implicit casting is the process of simply assigning one entity to another without any transformation guidance to the compiler. This type of casting is not permitted in all kinds of transformations and may not work for all scenarios.

Example

int i = 1000;

long j = i; //Implicit casting

Is sizeof a keyword in java?

The sizeof operator is not a keyword.

What is a native method?

A native method is a method that is implemented in a language other than Java.

In System.out.println(), what is System, out and println?

System is a predefined final class, out is a PrintStream object and println is a built-in overloaded method in the out object.

What are Encapsulation, Inheritance and Polymorphism

Explain the Polymorphism principle. Explain the different forms of Polymorphism.

Polymorphism in simple terms means one name many forms. Polymorphism enables one entity to be used as a general category for different types of actions. The specific action is determined by the exact nature of the situation.

Polymorphism exists in three distinct forms in Java:
• Method overloading
• Method overriding through inheritance
• Method overriding through the Java interface

What is explicit casting?

Explicit casting in the process in which the complier are specifically informed to about transforming the object.

Example

long i = 700.20;

int j = (int) i; //Explicit casting

What is the Java Virtual Machine (JVM)?

The Java Virtual Machine is software that can be ported onto various hardware-based platforms

What do you understand by downcasting?

The process of Downcasting refers to the casting from a general to a more specific type, i.e. casting down the hierarchy

What are Java Access Specifiers?

What is the difference between public, private, protected and default Access Specifiers?

What are different types of access modifiers?

Access specifiers are keywords that determine the type of access to the member of a class. These keywords are for allowing
privileges to parts of a program such as functions and variables. These are:
• Public : accessible to all classes
• Protected : accessible to the classes within the same package and any subclasses.
• Private : accessible only to the class to which they belong
• Default : accessible to the class to which they belong and to subclasses within the same package

Which class is the superclass of every class?

Object.

Name primitive Java types.

The 8 primitive types are byte, char, short, int, long, float, double, and boolean.

What is the difference between static and non-static variables?

What are class variables?

What is static in java?

What is a static method?

A static variable is associated with the class as a whole rather than with specific instances of a class. Each object will share a common copy of the static variables i.e. there is only one copy per class, no matter how many objects are created from it. Class variables or static variables are declared with the static keyword in a class. These are declared outside a class and stored in static memory. Class variables are mostly used for constants. Static variables are always called by the class name. This variable is created when the program starts and gets destroyed when the programs stops. The scope of the class variable is same an instance variable. Its initial value is same as instance variable and gets a default value when its not initialized corresponding to the data type. Similarly, a static method is a method that belongs to the class rather than any object of the class and doesn’t apply to an object or even require that any objects of the class have been instantiated.
Static methods are implicitly final, because overriding is done based on the type of the object, and static methods are attached to a class, not an object. A static method in a superclass can be shadowed by another static method in a subclass, as long as the original method was not declared final. However, you can’t override a static method with a non-static method. In other words, you can’t change a static method into an instance method in a subclass.

Non-static variables take on unique values with each object instance.

What is the difference between the boolean & operator and the && operator?

If an expression involving the boolean & operator is evaluated, both operands are evaluated, whereas the && operator is a short cut operator. When an expression involving the && operator is evaluated, the first operand is evaluated. If the first operand returns a value of true then the second operand is evaluated. If the first operand evaluates to false, the evaluation of the second operand is skipped.

How does Java handle integer overflows and underflows?

It uses those low order bytes of the result that can fit into the size of the type allowed by the operation.

What if I write static public void instead of public static void?

Program compiles and runs properly.

What is the difference between declaring a variable and defining a variable?

In declaration we only mention the type of the variable and its name without initializing it. Defining means declaration + initialization. E.g. String s; is just a declaration while String s = new String (”bob”); Or String s = “bob”; are both definitions.

What type of parameter passing does Java support?

In Java the arguments (primitives and objects) are always passed by value. With objects, the object reference itself is passed by value and so both the original reference and parameter copy both refer to the same object.

Explain the Encapsulation principle.

Encapsulation is a process of binding or wrapping the data and the codes that operates on the data into a single entity. This keeps the data safe from outside interface and misuse. Objects allow procedures to be encapsulated with their data to reduce potential interference. One way to think about encapsulation is as a protective wrapper that prevents code and data from being arbitrarily accessed by other code defined outside the wrapper.

What do you understand by a variable?

Variable is a named memory location that can be easily referred in the program. The variable is used to hold the data and it can be changed during the course of the execution of the program.

What do you understand by numeric promotion?

The Numeric promotion is the conversion of a smaller numeric type to a larger numeric type, so that integral and floating-point operations may take place. In the numerical promotion process the byte, char, and short values are converted to int values. The int values are also converted to long values, if necessary. The long and float values are converted to double values, as required.

What do you understand by casting in java language? What are the types of casting?

The process of converting one data type to another is called Casting. There are two types of casting in Java; these are implicit casting and explicit casting.

What is the first argument of the String array in main method?

The String array is empty. It does not have any element. This is unlike C/C++ where the first element by default is the program name. If we do not provide any arguments on the command line, then the String array of main method will be empty but not null.

How can one prove that the array is not null but empty?

Print array.length. It will print 0. That means it is empty. But if it would have been null then it would have thrown a NullPointerException on attempting to print array.length.

Can an application have multiple classes having main method?

Yes. While starting the application we mention the class name to be run. The JVM will look for the main method only in the class whose name you have mentioned. Hence there is not conflict amongst the multiple classes having main method.

When is static variable loaded? Is it at compile time or runtime? When exactly a static block is loaded in Java?

Static variable are loaded when classloader brings the class to the JVM. It is not necessary that an object has to be created. Static variables will be allocated memory space when they have been loaded. The code in a static block is loaded/executed only once i.e. when the class is first initialized. A class can have any number of static blocks. Static block is not member of a class, they do not have a return statement and they cannot be called directly. Cannot contain this or super. They are primarily used to initialize static fields.

Can I have multiple main methods in the same class?

We can have multiple overloaded main methods but there can be only one main method with the following signature :

public static void main(String[] args) {}

No the program fails to compile. The compiler says that the main method is already defined in the class.

Explain working of Java Virtual Machine (JVM)?

JVM is an abstract computing machine like any other real computing machine which first converts .java file into .class file by using Compiler (.class is nothing but byte code file.) and Interpreter reads byte codes.

How can I swap two variables without using a third variable?

Add two variables and assign the value into First variable. Subtract the Second value with the result Value. and assign to Second variable. Subtract the Result of First Variable With Result of Second Variable and Assign to First Variable. Example:

int a=5,b=10;a=a+b; b=a-b; a=a-b;

An other approach to the same question

You use an XOR swap.

for example:

int a = 5; int b = 10;
a = a ^ b;
b = a ^ b;
a = a ^ b;

What is data encapsulation?

Encapsulation may be used by creating ‘get’ and ’set’ methods in a class (JAVABEAN) which are used to access the fields of the object. Typically the fields are made private while the get and set methods are public. Encapsulation can be used to validate the data that is to be stored, to do calculations on data that is stored in a field or fields, or for use in introspection (often the case when using javabeans in Struts, for instance). Wrapping of data and function into a single unit is called as data encapsulation. Encapsulation is nothing but wrapping up the data and associated methods into a single unit in such a way that data can be accessed with the help of associated methods. Encapsulation provides data security. It is nothing but data hiding.

What is reflection API? How are they implemented?

Reflection is the process of introspecting the features and state of a class at runtime and dynamically manipulate at run time. This is supported using Reflection API with built-in classes like Class, Method, Fields, Constructors etc. Example: Using Java Reflection API we can get the class name, by using the getName method.

Does JVM maintain a cache by itself? Does the JVM allocate objects in heap? Is this the OS heap or the heap maintained by the JVM? Why

Yes, the JVM maintains a cache by itself. It creates the Objects on the HEAP, but references to those objects are on the STACK.

What is phantom memory?

Phantom memory is false memory. Memory that does not exist in reality.

Can a method be static and synchronized?

A static method can be synchronized. If you do so, the JVM will obtain a lock on the java.lang.
Class instance associated with the object. It is similar to saying:

synchronized(XYZ.class) {

}

What is difference between String and StringTokenizer?

A StringTokenizer is utility class used to break up string.

Example:

StringTokenizer st = new StringTokenizer(”Hello World”);

while (st.hasMoreTokens()) {

System.out.println(st.nextToken());

}

Output:

Hello

World

Java And Internet

2010-08-14T02:34:00.000-07:00

Java And Internet

2010-08-14T02:28:00.000-07:00

Why java is important to the Internet

The Internet helped catapult java to the forefront of programming, and java, in turn, has had a profound effect on the Internet. The reason for this is quite simple: Java expands the universe of objects that can move about freely in cyberspace. In a network, two very broad categories of objects are transmitted between the server and your personal computer: passive information and dynamic, active programs. For example, when you read your e-mail, you are viewing passive data. Even when you download a program, the program’s code is still only passive data. Even when you download a second type of object can be transmitted to your computer: a dynamic, self-executing program. Such a program is and the server yet initiates active agent on the client computer. For example, the server to display properly the data that the server is sending might provide a program.

As desirable as dynamic, networked programs are, they also present serious problems in the areas of security and portability. Prior to java, cyberspace was effectively closed to half the entities that now live there, as you will see, java addresses those concerns and, by doing so, has opened the door to an exciting new form of program: the applet.

Java Applets and Applications

Java can be used to create two types of programs: applications and applets. An application is a program that runs on your computer, under the operating system of that computer. That is , an application created by java is more or less like one created using C or C++. When used to create applications, java is a not much different from any other computer language. Rather, it is java’s ability to create applets that makes it important. An applet is an application designed to be transmitted over the Internet and executed by a java-compatible Web browser. An applet is actually a tiny java program, dynamically downloaded across the network, just like an image, sound file, or video clip. The important difference is that an applet is an intelligent program, not just and animation or media file. In other words, and applet is a program that can react to user input and dynamically change not just run the same animation or sound over and over.

Security

As you are likely aware, every time that you download a “normal ” program, you are risking a viral infection. Prior to java, most users did not download executable programs frequently, and those who did scanned them for viruses prior to execution. Even so, most users still worried about the possibility of infection their systems with a virus. In addition to viruses, another type of maillicious program exists that must be guarded against. This type of program can gather private information, such as credit card numbers, bank account balances, and passwords, by searching the contents of your computer’s local file system, java answer both of these concerns by providing a “firewall” between a networked application and your computer.

Portability

Many types of computers and operating systems are in use throughout the world - and many are connected to the Internet. For programs to be dynamically downloaded to all the various types of platforms connected to the Internet, some means of generating portable executable code is needed. As you will soon see, the same mechanism that helps ensure security also helps create portability. Indeed, java’s solution to these two problems is both elegant and efficient.

Java Platform, Enterprise Edition

2010-08-13T08:55:00.000-07:00

Java Platform, Enterprise Edition (Java EE) 6 is the industry standard for enterprise Java computing. Utilize the new, lightweight Java EE 6 Web Profile to create next-generation web applications, and the full power of the Java EE 6 platform for enterprise applications. Developers will benefit from productivity improvements with more annotations, more POJOs, simplified packaging, and less XML configuration.

Computer Education: Programming In C++

2010-08-12T10:29:00.000-07:00

Computer Education: Programming In C++: "Probably the best way to start learning a programming language is by writing a program. Therefore, here is our first program: // my fir..."

Computer Education: Importance Of Java Programming

2010-08-12T10:23:00.000-07:00

Computer Education: Importance Of Java Programming: "Java is a programming language distinct from the markup scheme for defining hypertext, the Hypertext Markup Language (HTML). Java doesn..."

Importance Of Java Programming

2010-08-12T09:47:00.000-07:00

Java is a programming language distinct from the markup scheme for defining hypertext, the Hypertext Markup Language (HTML). Java doesn't compete with or replace HTML, nor does it negate the work done creating content using HTML for the Web.

When it was released in the spring of 1995 by Sun Microsystems, Java unleashed a level of interactivity on the Web that had never been possible before. Java makes the Web interactive.

Java connects with HTML and the Web through a special HTML element called APPLET, which allows developers to include Java programs called applets on Web pages. These applets are essentially software programs that the user's browser downloads (automatically, as part of Web page observation) and executes. With real-time graphical input and output possible through the applet on the page, Java thus opens windows to into richer levels of interactivity and visualization.

What is the Big Deal About Java?

Prior to 1995, people and organizations had been using webs of hypermedia on the World Wide Web to communicate globally and instantly. But something was missing. The often intriguing, informative, and useful Web content was devoid of much interactivity. Some users felt that the hyperlinks on the Web just kept leading them on, until ultimately, the Web seemed like a road to nowhere: with no there there. Java potentially changes this.

Java enables developers to create content that can be delivered to and run by users on their computers. This content is in the form of software that can support anything that programmers can dream up: spreadsheets, tutorials, animations, and interactive games. With the Web page as the delivery platform, this software can support a variety of information tasks with true interactivity: for example, users can get continuous, instantaneous feedback for applications in visualization, animation and computation. Users of the Web in Java age may indeed find a there on the Web: a place to play, work, or learn.

Who is Using Java?

Many companies have made a decision to use Java as the language for their software development. As the first interactive language for the Web content, Java got a good head-start, resulting in a good base of experience and skills among programmers. With Sun Microsystems' committment to Java, it looks like Java is a good choice for Internet content development.

My Opinion of Java

I was very excited about Java when it was released in the spring of 1995. I spent the summer of 1995 writing the first published Java book and, in it, I was enthusiastic with my first experience of Java. I saw so much potential.

Yet today, I see results with Java that are far, far less than what I had imagined. More than two years from its invention (two years is aeons in Internet time), Java really isn't used as extensively as I thought it would be. I think the reasons for this lie not in the language--it is actually a very good language. Instead, I think these issues have held Java back:

Web developer's attention was scattered during the period 1995-1996 with many new technologies (Shockwave, JavaScript [JavaScript has nothing to do with Java], ActiveX) that all seemed to promise a richer and more interactive Web. The tragedy of the JavaScript name, for example, lulled (and still lulls) many Web developers to squander their skills on buggy, non-standard, JavaScript code on HTML pages.
Many Web developer's lack the skills to create useful interactivity in Web pages. Java is a software language--it is not something that a person can pick up as easily as HTML. Java requires a solid understanding of object-oriented development methodologies and implementation practices, besides good software engineering skills. And since Java is used to create interactivity on Web pages, developers need to know about human-computer interface design. And since Java can be used to mediated human communication (in groupware, for example), developers should understanding computer-mediated communication issues. What this means is that someone who wants to do serious Java development should be a specialist. Amateur users can learn Java in 14 days and create "toy" applets, but the level of their work would be far below the power and potential of Java itself. My feeling is that it is a tragedy that few people realize this distinction and instead dink around with silly animations and toy applets on their pages and believe they are creating "interactive content."
Java class libraries are just coming into existence. The raw Java Developer's Toolkit that Sun provides for free shouldn't be the basis for serious Java development--this is like starting to build a car using molten metal, plastic, and glass to create the screws, parts, and mechanisms that will make up the components. Instead, Java developers need to stand on the shoulders of giants and start building serious, complex applications using components and subsystems, not raw materials.

I think in the long run, Java is a good choice for development. I think the advances in Java compilation and run-time support in the latest versions of Web browsers should support a more pleasing experience for users of Java applets. I think that, in several years, developers may eventually grasp the importance of Java as a bridge of human communication online. I think then we'll begin to see the potential of Java.

Java Script Language

2010-08-10T22:48:00.000-07:00

Overview

This document is an introduction to the JavaScript Programming Language for professional programmers. It is a small language, so if you are familiar with other languages, then this won't be too demanding.

JavaScript is not Java. They are two very different languages. JavaScript is not a subset of Java. It is not interpreted Java. (Java is interpreted Java!) JavaScript shares C-family syntax with Java, but at a deeper level it shows greater similarity to the languages Scheme and Self. It is a small language, but it is also a suprisingly powerful and expressive language.You should take a look at it. You will find that it is not a toy language, but a full programming language with many distinctive properties.

JavaScript is a regular language which won't take much time to learn. It is better suited to some tasks, such as client programming, than Java is. In my own practice, I have found that working with JavaScript has made me a better Java programmer because it introduced me to a useful set of dynamic techniques.

When JavaScript was first introduced, I dismissed it as being not worth my attention. Much later, I took another look at it and discovered that hidden in the browser was an excellent programming language. My initial attitudes were based on the initial positioning of JavaScript by Sun and Netscape. They made many misstatements about JavaScript in order to avoid positioning JavaScript as a competitor to Java. Those misstatements continue to echo in the scores of badly written JavaScript books aimed at the dummies and amateurs market.

History

JavaScript was developed by Brendan Eich at Netscape as the in-page scripting language for Navigator 2. It is a remarkably expressive dynamic programming language. Because of its linkage to web browsers, it instantly became massively popular. It never got a trial period in which it could be corrected and polished based on actual use. The language is powerful and flawed.

This document describes ECMAScript Edition 3 (aka JavaScript 1.5). Microsoft and Netscape are developing a static revision which does not correct the language's flaws. That new language is not JavaScript and is beyond the scope of this document.

JavaScript is THE scripting language of the Web.

JavaScript is used in millions of Web pages to add functionality, validate forms, detect browsers, and much more.

Java Applet Programming

2010-08-10T04:46:00.000-07:00

History

It was originally called Oak, developed by SUN Microsystems, in a project called FirstPerson for smart appliances, such as set-top-box (interactive TV) 1992, lead by James Gosling.
It adopted C++ syntax but get rid of pointer, memory management, and multiple inheritance, which are main causes of programming errors.
It failed to be adopted by Timer Warner in Spring 93's ITV trial.
1993 Marc Andreesen developed Mosaic Web Browser, started the web revolution.
Oak found its reason for existence. A Web browser called WebRunner was developed for demonstration.
January 1995, Sun adopted Java name due to trademark issue.
Marc Andreesen saw the demo and license it for use in its browser.
Nov. 1995, 1st Beta release with developer kit and source code.

What is Java Applet

Java is a general purpose programming language.
A Java program is created as a text file with .java extension.
It is compiled into one or more files of bytecodes with .class extension.
Bytecodes are a set of instructions similar to machine code of a specific machine but it can be run on any machine that has a Java Virtual Machine (JVM). JVM interprets bytecodes.
JVM was first implemented on Sparc/Solaris and PC/Win32. Now ported to many other platforms.
Java applets are Java programs that are retrieved and executed by web browsers through the JVM under tight secure environment.
Web browsers retrieve Java applets according to following tags in the web pages:

deprecated or the new more general,

height=500>

are used to specify parameters for the applet. For example,
-- the height (in pixels) of the tallest frame
-- the directory that has the animation frames (gif, jpg)

All other types of java programs are called Java applications.

Examples:

Network Restoration Applet: User specifies two end node of a failed link. The applet retrieves the simulation results of two network restoration algorithms (twoprong and rreact) in two corresponding files at original web server site, and plot the results.

SUN Java demos:

MoleculeViewer
SimpleGraph
SortDemo
BarChart
Animator
JumpingBo

About The Java Technoogy

2010-07-16T18:01:00.000-07:00

To date, the Java platform has attracted more than 6.5 million software developers. It's used in every major industry segment and has a presence in a wide range of devices, computers, and networks.

Java technology's versatility, efficiency, platform portability, and security make it the ideal technology for network computing. From laptops to datacenters, game consoles to scientific supercomputers, cell phones to the Internet, Java is everywhere!

Java powers more than 4.5 billion devices including:

850+ million PCs
2.1 billion mobile phones and other handheld devices (source: Ovum)
3.5 billion smart cards
Set-top boxes, printers, Web cams, games, car navigation systems, lottery terminals, medical devices, parking payment stations, and more.

To see places of Java in Action in your daily life, explore java.com.

Why Software Developers Choose Java

Java has been tested, refined, extended, and proven by a dedicated community. And numbering more than 6.5 million developers, it's the largest and most active on the planet. With its versatilty, efficiency, and portability, Java has become invaluable to developers by enabling them to:

Write software on one platform and run it on virtually any other platform
Create programs to run within a Web browser and Web services
Develop server-side applications for online forums, stores, polls, HTML forms processing, and more
Combine applications or services using the Java language to create highly customized applications or services
Write powerful and efficient applications for mobile phones, remote processors, low-cost consumer products, and practically any other device with a digital heartbeat

Some Ways Software Developers Learn Java

Today, many colleges and universities offer courses in programming for the Java platform. In addition, developers can also enhance their Java programming skills by reading Sun's java.sun.com Web site, subscribing to Java technology-focused newsletters, using the Java Tutorial and the New to Java Programming Center, and signing up for Web, virtual, or instructor-led courses.

What Is JavaFX

JavaFX extends your web experience by delivering rich media and content across all the screens of your life. As users, you will be able to run JavaFX applications in a browser or drag and drop them onto the desktop. It's a seamless interface!

JavaFX is powered by Java: JavaFX extends the power of Java by allowing developers to use any Java library within JavaFX applications. This way developers can expand their capabilities in Java and make use of the revolutionary presentation technology that JavaFX provides to build engaging visual experiences.

Highlights of JavaFX:

Allows users to view JavaFX applications in a browser or break free of the browser by dragging and dropping the same application onto the desktop
Enables an efficient designer-to-developer workflow with Project Nile: designers can work in their tools of choice while collaborating with Web scripters who use the NetBeans IDE with JavaFX
Extends Java technology by enabling use of any Java library within a JavaFX application
Allows developers to integrate vector graphics, animation, audio, and video Web assets into a rich, interactive, immersive application

To learn more about JavaFX technology, visit javafx.com or java.sun.com/javafx web sites for more information.

Programming In C++

2010-07-15T23:50:00.000-07:00

Probably the best way to start learning a programming language is by writing a program. Therefore, here is our first program:

// my first program in C++

#include 
using namespace std;

int main ()
{
cout << "Hello World!";
return 0;
}

(Hello World!)

The first panel (in light blue) shows the source code for our first program. The second one (in light gray) shows the result of the program once compiled and executed. To the left, the grey numbers represent the line numbers - these are not part of the program, and are shown here merely for informational purposes.

The way to edit and compile a program depends on the compiler you are using. Depending on whether it has a Development Interface or not and on its version. Consult the compilers section and the manual or help included with your compiler if you have doubts on how to compile a C++ console program.

The previous program is the typical program that programmer apprentices write for the first time, and its result is the printing on screen of the "Hello World!" sentence. It is one of the simplest programs that can be written in C++, but it already contains the fundamental components that every C++ program has. We are going to look line by line at the code we have just written:

// my first program in C++: This is a comment line. All lines beginning with two slash signs (//) are considered comments and do not have any effect on the behavior of the program. The programmer can use them to include short explanations or observations within the source code itself. In this case, the line is a brief description of what our program is.
#include: Lines beginning with a hash sign (#) are directives for the preprocessor. They are not regular code lines with expressions but indications for the compiler's preprocessor. In this case the directive #include tells the preprocessor to include the iostream standard file. This specific file (iostream) includes the declarations of the basic standard input-output library in C++, and it is included because its functionality is going to be used later in the program.
using namespace std;: All the elements of the standard C++ library are declared within what is called a namespace, the namespace with the name std. So in order to access its functionality we declare with this expression that we will be using these entities. This line is very frequent in C++ programs that use the standard library, and in fact it will be included in most of the source codes included in these tutorials.
int main (): This line corresponds to the beginning of the definition of the main function. The main function is the point by where all C++ programs start their execution, independently of its location within the source code. It does not matter whether there are other functions with other names defined before or after it - the instructions contained within this function's definition will always be the first ones to be executed in any C++ program. For that same reason, it is essential that all C++ programs have a main function.

The word main is followed in the code by a pair of parentheses (()). That is because it is a function declaration: In C++, what differentiates a function declaration from other types of expressions are these parentheses that follow its name. Optionally, these parentheses may enclose a list of parameters within them.

Right after these parentheses we can find the body of the main function enclosed in braces ({}). What is contained within these braces is what the function does when it is executed.
cout << "Hello World!";: This line is a C++ statement. A statement is a simple or compound expression that can actually produce some effect. In fact, this statement performs the only action that generates a visible effect in our first program.

cout is the name of the standard output stream in C++, and the meaning of the entire statement is to insert a sequence of characters (in this case the Hello World sequence of characters) into the standard output stream (cout, which usually corresponds to the screen).

cout is declared in the iostream standard file within the std namespace, so that's why we needed to include that specific file and to declare that we were going to use this specific namespace earlier in our code.

Notice that the statement ends with a semicolon character (;). This character is used to mark the end of the statement and in fact it must be included at the end of all expression statements in all C++ programs (one of the most common syntax errors is indeed to forget to include some semicolon after a statement).
return 0;: The return statement causes the main function to finish. return may be followed by a return code (in our example is followed by the return code with a value of zero). A return code of 0 for the main function is generally interpreted as the program worked as expected without any errors during its execution. This is the most usual way to end a C++ console program.

You may have noticed that not all the lines of this program perform actions when the code is executed. There were lines containing only comments (those beginning by //). There were lines with directives for the compiler's preprocessor (those beginning by #). Then there were lines that began the declaration of a function (in this case, the main function) and, finally lines with statements (like the insertion into cout), which were all included within the block delimited by the braces ({}) of the main function.

The program has been structured in different lines in order to be more readable, but in C++, we do not have strict rules on how to separate instructions in different lines. For example, instead of

int main ()
{
cout << " Hello World!";
return 0;
}

We could have written:

int main () { cout << "Hello World!"; return 0; }

All in just one line and this would have had exactly the same meaning as the previous code.

In C++, the separation between statements is specified with an ending semicolon (;) at the end of each one, so the separation in different code lines does not matter at all for this purpose. We can write many statements per line or write a single statement that takes many code lines. The division of code in different lines serves only to make it more legible and schematic for the humans that may read it.

Let us add an additional instruction to our first program:

// my second program in C++

#include 

using namespace std;

int main ()
{
cout << "Hello World! ";
cout << "I'm a C++ program";
return 0;
}

(Hello World! I'm a C++ program)

In this case, we performed two insertions into cout in two different statements. Once again, the separation in different lines of code has been done just to give greater readability to the program, since main could have been perfectly valid defined this way:

int main () { cout << " Hello World! "; cout << " I'm a C++ program "; return 0; }

We were also free to divide the code into more lines if we considered it more convenient:

int main ()
{
cout <<    "Hello World!";
cout
  << "I'm a C++ program";
return 0;
}

And the result would again have been exactly the same as in the previous examples.

Preprocessor directives (those that begin by #) are out of this general rule since they are not statements. They are lines read and processed by the preprocessor and do not produce any code by themselves. Preprocessor directives must be specified in their own line and do not have to end with a semicolon (;).

Comments

Comments are parts of the source code disregarded by the compiler. They simply do nothing. Their purpose is only to allow the programmer to insert notes or descriptions embedded within the source code.

C++ supports two ways to insert comments:

1 2

// line comment
/* block comment */

The first of them, known as line comment, discards everything from where the pair of slash signs (//) is found up to the end of that same line. The second one, known as block comment, discards everything between the /* characters and the first appearance of the */ characters, with the possibility of including more than one line.
We are going to add comments to our second program:

/* my second program in C++
 with more comments */

#include 
using namespace std;

int main ()
{
cout << "Hello World! ";     // prints Hello World!
cout << "I'm a C++ program"; // prints I'm a C++ program
return 0;
}

(Hello World! I'm a C++ program)

If you include comments within the source code of your programs without using the comment characters combinations //, /* or */, the compiler will take them as if they were C++ expressions, most likely causing one or several error messages when you compile it.

2010-07-14T18:39:00.000-07:00

.."

C++ TIPS

2010-07-14T18:32:00.000-07:00

Break and Continue Statements

A tutorial that tells about Break and Continue Statements in C++.

Goto Statement

A tutorial that tells about goto Statement in C++.

Classes

A tutorial that tells about Classes in C++.

Static Class Members

A tutorial that tells about Static Class Members in C++.

Constructors and Destructors

A tutorial that tells about Constructors and Destructors in C++.

Copy Constructor

A tutorial that tells about Copy Constructors in C++.

Dynamic Memory Allocation in Constructors

This tutorial demonstrates how you can dynamically allocate memory for member objects that are inside of a class.

Inheritance

A tutorial that tells about Inheritance in C++.

Constructors in Derived Class

A tutorial that tells about Constructors in Derived Class in C++.

Virtual Base Classes

A tutorial that tells about Virtual Base Classes in C++.

Pointers

A tutorial that tells about Pointers in C++.

This Pointer

A tutorial that tells about this Pointer in C++.

Arrays

A tutorial that tells about Arrays in C++.

Pointers and Arrays

A tutorial that tells about Pointers and Arrays in C++.

Preprocessor

A tutorial that tells about Preprocessors in C++.

Structures

A tutorial that tells about Structures in C++.

Functions

A tutorial that tells about Functions and how to pass parameters by value.

Call-By-Reference in Functions

A tutorial that tells about how to pass parameters, to a function, by reference.

Function Overloading

A tutorial that tells about a concept called Function Overloading.

Operator Overloading

This tutorial explains the concept of operator overloading. It also contains tutorials on how to overload unary and binary operators.

Type Conversion

Learn how to convert between basic to class, class to basic and class to class types.

Inline Function

A tutorial hat tells about Inline Functions.

Friend Function

A tutorial that tells about Friend Functions.

Virtual Functions

Learn how to use virtual functions and take advantage of dynamic
polymorphism, the essence of object oriented programming in C++.

If Statement

A tutorial that tells about execution of an if Statement.

Scope Resolution Operator

This tutorial tells about the scope resolution operator and its use for accessing class member names as well as hidden global names.

Conditional Operators and Switch Statements

A tutorial that tells about Conditional Operators and Switch Statements.

Iterations

A tutorial that tells about various available types of iterations and loops.

Recursion

A tutorial that tells about Recursion.

Exception Handling

A tutorial that tells about Exception Handling concepts.

Throw and Catch Mechanism

A tutorial that tells about Throw and Catch Mechanism in Exception Handling.

Exception Handling (continued)

A tutorial that tells few more concepts about Exception Handling.

Template

A tutorial that tells about a generic programming method called Templates.

Function Templates

A tutorial that tells about Function Templates.

Function Template Overloading

A tutorial that tells about Function Template Overloading.

Standard Library Functions

A tutorial that explains and lists many Standard Library Functions.

Standard Library Functions (continued - part1)

A tutorial that explains and lists many Standard Library Functions.

Standard Library Functions (continued - part2)

A tutorial that explains and lists many Standard Library Functions.

File Input/Output

A tutorial that tells about File Input/Output Operations.

File Manipulation

A tutorial that tells about File Manipulation.

Binary Tree - Inserting a Node

A tutorial that tells how to insert a node into Binary Search Tree.

Binary Tree - Searching a Node

A tutorial that tells how to search for a node in Binary Search Tree.

Binary Tree - Deleting a Node

A tutorial that tells how to delete a node from Binary Search Tree.

Graphs

A tutorial that tells about certain structures called Graphs.

Breadth First Search Algorithm

A tutorial that explains Breath First Search Algorithm which is used to traverse/search a graph/tree.

Depth First Search Algorithm

A tutorial that explains Depth First Search Algorithm which is used to traverse/search a graph/tree.

Kruskal's Algorithm

A tutorial that explains Kruskal's Algorithm.

Prim Algorithm

A tutorial that explains Prim Algorithm.

Address Calculation Sort

A tutorial that explains Address Calculation Sort.

Warshall's Algorithm

A tutorial that explains Warshall's Algorithm.

Priority Queues

A tutorial that explains about special kind of queues called Priority Queues.

Dijkstra Algorithm

A tutorial that explains the working of Dijkstra Algorithm.

C++ Datatypes Tutorial

A tutorial that tells about datatypes available in C++

C++ practically offers most of the necessary data types except for a basic data type string. This is a big trouble in C++ without such a good feature. Anyway, this c++ tutorial will discuss the basic data types necessary for C++ ...

C++ Array Tutorial

A tutorial that tells about Arrays and what's its importance in C++

C++ Arrays are the data structures which can be used to store consecutive values of the same data types. C++ Arrays can be declared for all c++ data types viz., int, float, double, char, struct, char etc., All the values are stored in consecutive memory locations. The values can be accessed by using the position of the stored value ...

C++ Class Tutorial

A tutorial that tells about class & how it can be created

A class in C++ is an encapsulation of data members and functions that manipulate the data. The class can also have some other important members which are architecturally important ...

Function Overloading Tutorial

A tutorial that tells about function overloading and how this concept is useful in creating C++ programs

Function overloading is the practice of declaring the same function with different signatures. The same function name will be used with different number of parameters and parameters of different type. But overloading of functions with different return types are not allowed ...

Static Functions Tutorial

A tutorial that talks about static functions and how it differs from normal functions

Static data types can be accessed without instantiation of the class in C++. This is applicable for static functions also ...

File I/O Tutorial

A tutorial that shows how to use File I/O classes and functions

File handling is an important part of all programs. Most of the applications will have their own features to save some data to the local disk and read data from the disk again. C++ File I/O classes simplify such file read/write operations for the programmer by providing easier to use classes...

Class Templates Tutorial

A tutorial that shows how to create class templates in C++

C++ Class Templates are used where we have multiple copies of code for different data types with the same logic. If a set of functions or classes have the same functionality for different data types, they becomes good candidates for being written as Templates ...

Overloading Operators Tutorial

A tutorial that explains the basics of operator overloading in c++

C++ overloading is the mechanism by which the language standard operators are used for customized operations of the classes. For example if we are trying to write a string class, we would very simply ask for "+" operator to handle string concatenation, "-" for removing one part of string from another etc ...

Dynamic Memory Allocation Tutorial

A tutorial that explains the fundamentals of memory allocation in a C++ program

So you have just finished your program and you would like to see it at work. Usually you press a combination of keys to compile and run it. But what actually happens when you press those keys ? The compilation process translates your code from C++ to machine language, which is the only language computers "understand". Then your application is given a certain amount of memory to use, which is divided into three segments as follows ...

Memory Leaks Tutorial

A tutorial that explains how a memory leak happens and gives some tips on how to avoid it

A memory leak is what happens when you forget to free a block of memory allocated with the new operator or when you make it impossible to do so. As a consequence your application may eventually run out of memory and may even cause the system to crash. I will now give you a few tips. Remember that code lines shown in red are the best alternative to each situation - they may be added or may even replace previous code ...

C Language Overview

2010-07-13T18:51:00.000-07:00

The following information describes some of the changes that are specific to C language programs:

Header file changes. The z/TPF-compatible compilers do not allow header file names with $ characters.
Differences between the IBM® C/C++ compiler and z/TPF-compatible compilers. For example, z/TPF-compatible compilers tend to be closer to ANSI compliance, while TPF 4.1 code, especially code that has not changed in a long time, will not be. You will probably have to change your application code based on what the results are when you compile your code with a z/TPF-compatible compiler. Some specific compiler differences are:
- The GCC does not support trigraphs (under most circumstances) while the Systems/C and Systems/C++ compilers do support trigraphs.
- The GCC expects the backslash (\) character to be the very last character on the line when it is used as a line continuation character.
64-bit considerations:
- With the z/TPF system, all C/C++ programs are compiled as 64 bit, which defines the size of a long data type as 8 bytes. With the TPF 4.1 system, all C/C++ programs are compiled as 32-bit, which defines the size of a long data type as 4 bytes. For both systems, the size of an integer data type is 4 bytes.
  To provide compatibility with the size of the fields contained in data structures that have corresponding assembler data areas (DSECTs), all long data types were changed to integer data types. As code was converted to 64 bit, selected fields were changed back to long data types as appropriate.
  
  You need to decide if the data type size change affects your applications and how you would like to make your changes.
- Another 64-bit consideration is the use of pointers. When a C/C++ program is compiled as 64-bit, the size of a pointer data type is 8 bytes. Sometimes pointers are cast to integers for various reasons. To create code that is compatible for both 32-bit and 64-bit systems, change the casting from integer to long. The z/TPF-compatible compilers may produce a warning for pointers that are cast to integers.
  There might be some instances where you will continue to need a 4-byte pointer; for example, pointers to core blocks in the ECB cannot be increased to 8 bytes. To provide compatibility, a 31-bit pointer attribute called PTR32ATT and 31-bit pointer data types called __ptr32_t, __chptr32_t, and __uiptr32_t are provided.
- When a C/C++ program passes a pointer to static or constant data to an assembler program, the called assembler program must handle the pointer as a true 64-bit pointer unless the C/C++ program is loaded below the 2-GB bar.
With the TPF 4.1 system, the standard template library is supported by STLPort. With the z/TPF system, the standard template library is supported by the GNU standard C++ library (libstdc++).
The TPF 4.1 system supports floating point data only in hexadecimal floating point (HFP) format. However, ELF-compatible compilers (and the z/TPF system) support only binary floating point (BFP) format. You can use the following functions to migrate your floating point data, and to maintain single source applications that run under both the TPF 4.1 system and the z/TPF system:
- tpf__fp_htob
- tpf__fp_btoh
- tpf__fp_hton
- tpf__fp_ntoh
- tpf__fp_bton
- tpf__fp_ntob.

Programming In C Language

2010-07-12T18:17:00.000-07:00

The notes on these pages are for the courses in C Programming I used to teach in the Experimental College at the University of Washington in Seattle, WA. Normally these notes accompany fairly traditional classroom lecture presentations, but they are intended to be reasonably complete (more so, for that matter, than the lectures!) and should be usable as standalone tutorials.

I originally designed the first, Introductory course around The C Programming Language (2nd Edition) by Kernighan and Ritchie, and the notes were designed to complement that text, highlighting important points and explaining subtleties which might be lost on the general reader. Later, I rewrote the notes to stand on their own (in part because, in spite of the first set of notes, too many of my students found K&R a bit too technical for an informal, introductory course). Finally, I occasionally teach an Intermediate course, which covers the topics which tend to be skipped or glossed over in introductory courses (bitwise operators, structures, file I/O, etc.). The Intermediate course has its own set of notes.

All three sets of notes are available here. If you have a copy of K&R2 and would like a thorough treatment of the language, read K&R and the ``Notes to Accompany K&R'' side by side. If you're just getting your feet wet and would like a somewhat simpler introduction, read the ``Introductory Class Notes.'' If you have had an introduction to C (either here or elsewhere) and are now looking to fill in some of the missing pieces, read the ``Intermediate Class Notes.''

Of course, just reading a book or these notes won't really teach you C; you will also want to write and run your own programs, for practice and so that the language concepts will make some kind of practical sense. Most of my programming assignments (including review questions) are here as well, along with their solution sets. (No peeking at the answers until you've given the problems your best shot!)

These notes are arranged for the web in the usual hierarchy by section and subsection. If you want to read through all of them, without keeping track of your own stack to implement a depth-first tree traversal, just follow the ``read sequentially'' links at the bottom of each page.

Depending on your background, you might want to read one or both of the two preliminary handouts: one on programming in general, and one which reviews some math which is relevant to programming. (And there are some other miscellaneous handouts, too.)

One note about the HTML: these pages were produced automatically from the base manuscripts for my class notes, using a program of my own devising which is, all too typically, not (yet?) perfect. I apologize in advance for any formatting glitches. In particular, when you see ^... or _... in the text, these do not represent bugs in your browser or accidental bugs in my markup; instead, these are my interim compromise way of representing superscripts and subscripts to you, since there's no way to do so in portable HTML.

Finally, I realize that reading these notes on the net is not always as convenient as it might be, particularly when the net is slow. Please realize, though, that the net is what it is, and that I have gone to a certain amount of effort to place these notes here at all. Please do not ask me to send you a set of these notes for browsing on your own machine, as I am currently unable to do so.

C LANGUAGE AND ITS IMPORTANCE

2010-07-11T23:39:00.000-07:00

The C programming language was developed by Dennis Ritchie at Bell Labs between 1968 and 1972 for Unix systems. Ritchie derived the features of C from the earlier language B, which is why he chose the name. Today, C has become one of the most popular languages. C's influence can be seen throughout many more recent programming languages, especially C++. Many of C's advantages are because of its age and commonality.

Maturity

C has been around for a very long time in terms of computer programming. Almost every aspect of the language, including tricks that weren't intended by the original developers, has been explored and clearly explained. There are a wealth of examples and reusable source code freely available on the Internet.

Portability

Today, there are very few platforms that do not have a C compiler. This means that, with some minor tinkering, almost any C program can be compiled to run on almost any platform. C originated as a language for writing computer system software but has since been used extensively for developing application software for portable platforms such as smartphones.

Common Language

Because C is so widely used and well understood, it is a great tool for expressing programming ideas in a way that others can comprehend, regardless of the language they are most familiar with. C can also be seen as archetypal for many later languages. Language constructs in C, such as "if" statements, "for" and "while" loops, and types of variables, can be found in many more modern languages, so ideas expressed in C can still be understood by program developers.

Low-Level Power

Although C is technically a high-level language, meaning it abstracts programming away from the basic machine code; it is one of the "lowest-level" high-level programming languages. C code exerts powerful, direct and close control over the machine. Because C is linked so closely with the machine, it provides methods for direct access to system components like the hard disk drive, optical drives and printers.

Procedural Language

C is a procedural programming language, not an object-oriented programming language. However, despite the wide use of object-oriented design in modern programming, many applications are still better suited to the procedural style of design, which often goes untaught to many many programmers, who focus exclusively on object-oriented design. Learning C provides a strong procedural background, which is a worthy skill set.

Relationship to C+++

C++ began as an extension to the C programming language, but it eventually developed into a fully object-oriented language of its own. However, because it shares the majority of its syntax and structure from C, it is a simple task to transition from C to C++, or from C++ to C.