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Sabtu, 17 Januari 2009
C++ Programming Language
C++
What is C ?
C is an imperative (procedural) systems implementation language. It was designed to be compiled using a relatively straightforward compiler, to provide low-level access to memory, to provide language constructs that map efficiently to machine instructions, and to require minimal run-time support. C was therefore useful for many applications that had formerly been coded in assembly language.
Why is C popular?
In computing, C is a general-purpose computer programming language originally developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system.
Although C was designed for implementing system software, it is also widely used for developing application software.
It is widely used on many different software platforms and computer architectures, and several popular C compilers exist. C has greatly influenced many other popular programming languages, most notably C++, which originally began as an extension to C.
Areas of Use
C++ is used to develop applications in a number of different areas. Some of them are listed below:
* Commerce
* Education
* Marketing and Sales
* etc
History
The initial development of C occurred at AT&T Bell Labs between 1969 and 1973; according to Ritchie, the most creative period occurred in 1972. It was named "C" because many of its features were derived from an earlier language called "B", which according to Ken Thompson was a stripped-down version of the BCPL programming language.
The origin of C is closely tied to the development of the Unix operating system, originally implemented in assembly language on a PDP-7 by Ritchie and Thompson, incorporating several ideas from colleagues. Eventually they decided to port the operating system to a PDP-11. B's lack of functionality to take advantage of some of the PDP-11's features, notably byte addressability, led to the development of an early version of the C programming language.
The original PDP-11 version of the Unix system was developed in assembly language. By 1973, with the addition of struct types, the C language had become powerful enough that most of the Unix kernel was rewritten in C. This was one of the first operating system kernels implemented in a language other than assembly. (Earlier instances include the Multics system (written in PL/I), and MCP (Master Control Program) for the Burroughs B5000 written in ALGOL in 1961.)
The Advantages
-Compiled language - always runs fast.
-Standardized language (ANSI)- easier to port to different compilers / target devices.
-Many compilers available.
-Many in built functions (depending on compiler).
-Very popular – large user base with many example programs.
-Used in many different industries.
-Usable at the hardware level as well as higher abstraction levels (although C++ is better for very abstracted programming models).
The Disadvantages
-Hard to learn at first.
-Strong type checking means you spend time pleasing the compiler (although this protects you from making errors).
The Syntax
long int SomeFunction();
/* int OtherFunction(); */
/* int */ CallingFunction()
{
long int test1;
register /* int */ test2;
test1 = SomeFunction();
if (test1 > 0)
test2 = 0;
else
test2 = OtherFunction();
return test2;
}
What is C ?
C is an imperative (procedural) systems implementation language. It was designed to be compiled using a relatively straightforward compiler, to provide low-level access to memory, to provide language constructs that map efficiently to machine instructions, and to require minimal run-time support. C was therefore useful for many applications that had formerly been coded in assembly language.
Why is C popular?
In computing, C is a general-purpose computer programming language originally developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system.
Although C was designed for implementing system software, it is also widely used for developing application software.
It is widely used on many different software platforms and computer architectures, and several popular C compilers exist. C has greatly influenced many other popular programming languages, most notably C++, which originally began as an extension to C.
Areas of Use
C++ is used to develop applications in a number of different areas. Some of them are listed below:
* Commerce
* Education
* Marketing and Sales
* etc
History
The initial development of C occurred at AT&T Bell Labs between 1969 and 1973; according to Ritchie, the most creative period occurred in 1972. It was named "C" because many of its features were derived from an earlier language called "B", which according to Ken Thompson was a stripped-down version of the BCPL programming language.
The origin of C is closely tied to the development of the Unix operating system, originally implemented in assembly language on a PDP-7 by Ritchie and Thompson, incorporating several ideas from colleagues. Eventually they decided to port the operating system to a PDP-11. B's lack of functionality to take advantage of some of the PDP-11's features, notably byte addressability, led to the development of an early version of the C programming language.
The original PDP-11 version of the Unix system was developed in assembly language. By 1973, with the addition of struct types, the C language had become powerful enough that most of the Unix kernel was rewritten in C. This was one of the first operating system kernels implemented in a language other than assembly. (Earlier instances include the Multics system (written in PL/I), and MCP (Master Control Program) for the Burroughs B5000 written in ALGOL in 1961.)
The Advantages
-Compiled language - always runs fast.
-Standardized language (ANSI)- easier to port to different compilers / target devices.
-Many compilers available.
-Many in built functions (depending on compiler).
-Very popular – large user base with many example programs.
-Used in many different industries.
-Usable at the hardware level as well as higher abstraction levels (although C++ is better for very abstracted programming models).
The Disadvantages
-Hard to learn at first.
-Strong type checking means you spend time pleasing the compiler (although this protects you from making errors).
The Syntax
long int SomeFunction();
/* int OtherFunction(); */
/* int */ CallingFunction()
{
long int test1;
register /* int */ test2;
test1 = SomeFunction();
if (test1 > 0)
test2 = 0;
else
test2 = OtherFunction();
return test2;
}
Java & JavaFX
Java & JavaFX
Right now, 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:
- 800+ 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 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.
HTML
What is HTML
HyperText Markup Language (HTML) is a language to specify the structure of documents for retrieval across the Internet using browser programs of the World Wide Web
HTML is an application of the Standard Generalized Markup Language (SGML) which is the International Standard (ISO 8879) for text markup. The principle is that text markup concentrates on structure rather than appearance, making the files more reuseable and leaving the visual details to the end-user software (like the browser you're reading this with now). For the reasons why, see Eliot Kimber's comments.
Details of the specification are in the IETF Draft and the HTML Document Type Description. There is a FAQ (Frequently-Asked Questions) document (also available by anonymous ftp from rtfm.mit.edu), and a new book on HTML and the WorldWideWeb out shortly.
Simon Spero (ses@tipper.oit.unc.edu) explained it as:
The HTML DTD with its very simple element structure is primarily intended for describing the structural elements that appear on hypertext pages. Not the structure of the documents that comprise those pages (it's too vanilla for that), but the pages themselves. Not the layout of the pages, but the structure.
In a hypertext browsing system, the page is the basic object into which elements are placed, and which is common to all documents across all display technologies. Much of the structure of a document might be implicitly expressed via links between pages.
In order for a page to be displayed and browsed through correctly on a variety of systems - one of the primary design goals for the web - the layout of a page must be described in a sufficiently abstract way as to make sense on a VT100, a NeXT, or an X workstation. This rule was broken somewhat by the tag, introduced by NCSA for their Xmosaic browser, but is otherwise generally intact. Attributes like centering are only really suitable for bitmapped displays with variable spacing. To allow portable display it is much better to indicate the visual role to be played by the attribute (the reason why you wanted it centered), and allow the display engine to decide how that text should be rendered.
The Universal Resource Locator
The Universal Resource Locator (URL) is the `address' of a resource in the Web. It could be a file, or an index, or some program that does processing: they all use the same format to refer to them by:
scheme://host[:port]/path/filename{#location|?indexterm}
Examples
ftp://www.ucc.ie/pub/sgml/p2sg.ps
http://www.ucc.ie/cgi-bin/acronym?url
gopher://ds.internic.net/
* wherescheme is one of http, ftp, gopher, wais or file, depending on the kind of service you want to access
* [square brackets] mean the :port is optional (the default port is the one for the scheme being used, so leave it out unless told otherwise)
* host is the Internet hostname of the machine where the server runs which provides the resource you are looking for, eg www.ucc.ie
* path is the directory path to the resource
* filename.type is the filename (including the filetype, if needed)
* location is the identity of a known location in a .html file being retrieved (egname attribute to an anchor element you know it has already been marked in the file by the author using the
* indexterm is a search term or argument to pass to the resource. This is only meaningful if you know the resource is a script or a program which can handle data input
There are two exceptions to this format, for Usenet news and for Telnet.
Telnet
The double slash between the scheme and the hostname is omitted. An optional UserID can be included before the hostname, separated by a colon and an `at' sign, to cause the browser to prompt the user to login with this UserID. There is no path, filename, location or indexterm, eg:
telnet://library:@iruccvax.ucc.ie
Usenet news
The double slash between the scheme and the hostname is omitted, and the hostname is also omitted, as it will default to whatever your browser's configuration points at, so the newsgroup name follows immediately after the scheme. It is possible to follow the newsgroup name with a hash mark and location, the value of the location being the news article ID, but this is not recommended, as most sites expire articles after a certain time, so the chances of an article persisting are very remote:
news:comp.infosystems.www.users
The Advantages :
-to build a content from website,weblogsite(BLOG)
-the logic element tag in HTML is as not difficult as C++, JAVA, C, Pascal, Delphi, etc
The Disadvantages :
-it was difficult in writing of this program
-need more spaces of memory
The Syntax
/* html open */
/*tag open body */
/* tag ol open */
1. vegetables
/* content of list */
2. milk
3. fruits
/* tag ol close */
/* tag body close */
/*html close */
HyperText Markup Language (HTML) is a language to specify the structure of documents for retrieval across the Internet using browser programs of the World Wide Web
HTML is an application of the Standard Generalized Markup Language (SGML) which is the International Standard (ISO 8879) for text markup. The principle is that text markup concentrates on structure rather than appearance, making the files more reuseable and leaving the visual details to the end-user software (like the browser you're reading this with now). For the reasons why, see Eliot Kimber's comments.
Details of the specification are in the IETF Draft and the HTML Document Type Description. There is a FAQ (Frequently-Asked Questions) document (also available by anonymous ftp from rtfm.mit.edu), and a new book on HTML and the WorldWideWeb out shortly.
Simon Spero (ses@tipper.oit.unc.edu) explained it as:
The HTML DTD with its very simple element structure is primarily intended for describing the structural elements that appear on hypertext pages. Not the structure of the documents that comprise those pages (it's too vanilla for that), but the pages themselves. Not the layout of the pages, but the structure.
In a hypertext browsing system, the page is the basic object into which elements are placed, and which is common to all documents across all display technologies. Much of the structure of a document might be implicitly expressed via links between pages.
In order for a page to be displayed and browsed through correctly on a variety of systems - one of the primary design goals for the web - the layout of a page must be described in a sufficiently abstract way as to make sense on a VT100, a NeXT, or an X workstation. This rule was broken somewhat by the tag, introduced by NCSA for their Xmosaic browser, but is otherwise generally intact. Attributes like centering are only really suitable for bitmapped displays with variable spacing. To allow portable display it is much better to indicate the visual role to be played by the attribute (the reason why you wanted it centered), and allow the display engine to decide how that text should be rendered.
The Universal Resource Locator
The Universal Resource Locator (URL) is the `address' of a resource in the Web. It could be a file, or an index, or some program that does processing: they all use the same format to refer to them by:
scheme://host[:port]/path/filename{#location|?indexterm}
Examples
ftp://www.ucc.ie/pub/sgml/p2sg.ps
http://www.ucc.ie/cgi-bin/acronym?url
gopher://ds.internic.net/
* wherescheme is one of http, ftp, gopher, wais or file, depending on the kind of service you want to access
* [square brackets] mean the :port is optional (the default port is the one for the scheme being used, so leave it out unless told otherwise)
* host is the Internet hostname of the machine where the server runs which provides the resource you are looking for, eg www.ucc.ie
* path is the directory path to the resource
* filename.type is the filename (including the filetype, if needed)
* location is the identity of a known location in a .html file being retrieved (egname attribute to an anchor element you know it has already been marked in the file by the author using the
* indexterm is a search term or argument to pass to the resource. This is only meaningful if you know the resource is a script or a program which can handle data input
There are two exceptions to this format, for Usenet news and for Telnet.
Telnet
The double slash between the scheme and the hostname is omitted. An optional UserID can be included before the hostname, separated by a colon and an `at' sign, to cause the browser to prompt the user to login with this UserID. There is no path, filename, location or indexterm, eg:
telnet://library:@iruccvax.ucc.ie
Usenet news
The double slash between the scheme and the hostname is omitted, and the hostname is also omitted, as it will default to whatever your browser's configuration points at, so the newsgroup name follows immediately after the scheme. It is possible to follow the newsgroup name with a hash mark and location, the value of the location being the news article ID, but this is not recommended, as most sites expire articles after a certain time, so the chances of an article persisting are very remote:
news:comp.infosystems.www.users
The Advantages :
-to build a content from website,weblogsite(BLOG)
-the logic element tag in HTML is as not difficult as C++, JAVA, C, Pascal, Delphi, etc
The Disadvantages :
-it was difficult in writing of this program
-need more spaces of memory
The Syntax
/* html open */
/*tag open body */
/* tag ol open */
1. vegetables
/* content of list */
2. milk
3. fruits
/* tag ol close */
/* tag body close */
/*html close */
Pascal
Pascal Programming Language
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.
History
Pascal is based on the ALGOL programming language and named in honor of the French mathematician and philosopher Blaise Pascal. Wirth subsequently developed the Modula-2 and Oberon, languages similar to Pascal. Before, and leading up to Pascal, Wirth developed the language Euler, followed by Algol-W.
Initially, Pascal was largely, but not exclusively, intended to teach students structured programming. Generations of students have "cut their teeth" on Pascal as an introductory language in undergraduate courses. Variants of Pascal have also frequently been used for everything from research projects to PC games and embedded systems. Newer Pascal compilers exist which are widely used.
Pascal was the primary high-level language used for development in the Apple Lisa, and in the early years of the Mac; parts of the original Macintosh operating system were hand-translated into Motorola 68000 assembly language from the Pascal sources. The popular typesetting system TeX by Donald E. Knuth was written in WEB, the original literate programming system, based on DEC PDP-10 Pascal, while an application like Total Commander was written in Delphi (i.e. Object Pascal).
Areas of use
Pascal is used to develop applications in a number of different areas. Some of them are listed below:
* Accounting
* Business
* Commerce
* Education
* Law
* Medicine
* Research
* Science
The Advantages
-Debugging is easier. If the procedure is well written, it will do one and only one thing, making it easier to check
-Lower maintenance cost. If you have the same code spread along your code, you have to remember where it is located and fix or at least cut and paste it several times
-You can reuse the code. For example, you may place your procedures in a library and later use it in another program.
-Greater understanding. Since the procedure is well defined and documented, someone interested won't have to scroll through the whole source in order to find the code he/she wants
-Easier tuning. Performance usually comes from changing small pieces of code. With procedures these pieces are naturally separated and side-effects from changing variables or code are less likely to happen.
The Disadvantages
-Not as popular as C – so not as many compilers.
-A bit wordy – it was originally intended as a teaching language.
-Not as flexible as C.
The Syntax
while a <> b do writeln('Waiting');
if a > b then writeln('Condition met')
else writeln('Condition not met');
for i := 1 to 10 do writeln('Iteration: ', i:1);
repeat
a := a + 1
until a = 10;
case i of
0: write('zero');
1: write('one');
2: write('two')
end;
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.
History
Pascal is based on the ALGOL programming language and named in honor of the French mathematician and philosopher Blaise Pascal. Wirth subsequently developed the Modula-2 and Oberon, languages similar to Pascal. Before, and leading up to Pascal, Wirth developed the language Euler, followed by Algol-W.
Initially, Pascal was largely, but not exclusively, intended to teach students structured programming. Generations of students have "cut their teeth" on Pascal as an introductory language in undergraduate courses. Variants of Pascal have also frequently been used for everything from research projects to PC games and embedded systems. Newer Pascal compilers exist which are widely used.
Pascal was the primary high-level language used for development in the Apple Lisa, and in the early years of the Mac; parts of the original Macintosh operating system were hand-translated into Motorola 68000 assembly language from the Pascal sources. The popular typesetting system TeX by Donald E. Knuth was written in WEB, the original literate programming system, based on DEC PDP-10 Pascal, while an application like Total Commander was written in Delphi (i.e. Object Pascal).
Areas of use
Pascal is used to develop applications in a number of different areas. Some of them are listed below:
* Accounting
* Business
* Commerce
* Education
* Law
* Medicine
* Research
* Science
The Advantages
-Debugging is easier. If the procedure is well written, it will do one and only one thing, making it easier to check
-Lower maintenance cost. If you have the same code spread along your code, you have to remember where it is located and fix or at least cut and paste it several times
-You can reuse the code. For example, you may place your procedures in a library and later use it in another program.
-Greater understanding. Since the procedure is well defined and documented, someone interested won't have to scroll through the whole source in order to find the code he/she wants
-Easier tuning. Performance usually comes from changing small pieces of code. With procedures these pieces are naturally separated and side-effects from changing variables or code are less likely to happen.
The Disadvantages
-Not as popular as C – so not as many compilers.
-A bit wordy – it was originally intended as a teaching language.
-Not as flexible as C.
The Syntax
while a <> b do writeln('Waiting');
if a > b then writeln('Condition met')
else writeln('Condition not met');
for i := 1 to 10 do writeln('Iteration: ', i:1);
repeat
a := a + 1
until a = 10;
case i of
0: write('zero');
1: write('one');
2: write('two')
end;
Microsoft Visual Basic
Visual Basic
What is Visual Basic?
Visual Basic is a "visual programming" environment for developing Windows (also Web now) applications. Visual Basic makes it possible to develop complicated applications very quickly. The programmer designs windows graphically, drags program elements from the Visual Basic Toolbox and writes basic code for each element. Visual Basic is "event-driven" which means that procedures are called automatically when the end user chooses menu items, clicks the mouse, moves objects on the screen, etc.
Why is Visual Basic popular?
Programmers have undergone a major change in many years of programming various machines. For example, what could take days to create an application in other programming languages like C, C++ could be done in hours with Visual Basic. Visual Basic provides many interesting sets of tools to aid us in building exciting applications. Visual Basic provides these tools to make our life far more easier because all the real hard code is already written for us.
Visual Basic is not only a programming language but also a true graphical development environment. This environment allows programmers with little programming experience to quickly develop powerful Windows applications. Visual Basic also has the ability to develop programs that can be used as a front-end application to a database system, serving as the user interface which collects user input and displays formatted output in a more appealing and useful form.
Visual Basic is very popular for the ease with which it allows the programmer to create nice looking graphical programs with less coding unlike many other languages that take thousands of lines of programmer keyed code. As the programmer works in the graphical environment much of the program code is automatically generated by the Visual Basic program.
Areas of Use
Using Visual Basic's tools we can quickly translate an abstract idea into a program design that we can actually see on the screen. VB encourages you to experiment, revise, correct, and network your design until the new project meets your requirements. However, most of all, it inspires your imagination and creativity. Visual Basic is ideal for developing applications that run on the Windows operating system. Developing applications with VB can be said to be a 3-step approach:
i) Design the appearance of application
ii) Assign property settings to the objects of the program
iii) Write the code to direct specific tasks at runtime
Visual Basic is used to develop applications in a number of different areas. Some of them are listed below:
* Accounting
* Business
* Commerce
* Consulting
* Education
* Law
* Marketing and Sales
* Medicine
* Research
* Science
Many of the things that we do with Visual Basic really aren’t very basic. The Visual Basic language is powerful, if you can imagine a programming task, it can be accomplished using Visual Basic.
History of Visual Basic
Microsoft first released Visual Basic in 1987. It was the first visual development tool from Microsoft, and it was to compete with C, C++, Pascal and other well-known programming languages. From the start, Visual Basic wasn't a hit. It wasn't until release 2.0 that people really discovered the potential of the language, and with release 3.0 it had become the fastest-growing programming language on the market.
Below is the order and the approximate year in which a new version of Visual Basic was released:
* 1991, VB1 Debuts
* 1992, VB2 Debuts
* 1993, VB3 Debut
* 1996, VB4 Debuts
* 1997, VB5 Debuts
* 1998, VB6 Debuts
* 2001, VB. NET Debuts
for syntax example:
Loops
For Loop
The For loop is the most popular loop. For loops enable us to execute a series of expressions multiple numbers of times. The For loop in VB .NET needs a loop index which counts the number of loop iterations as the loop executes. The syntax for the For loop looks like this:
For index=start to end[Step step]
[statements]
[Exit For]
[statements]
Next[index]
The index variable is set to start automatically when the loop starts. Each time in the loop, index is incremented by step and when index equals end, the loop ends.
Example on For loop
Module Module1
Sub Main()
Dim d As Integer
For d = 0 To 2
System.Console.WriteLine("In the For Loop")
Next d
End Sub
End Module
While loop
While loop keeps executing until the condition against which it tests remain true. The syntax of while loop looks like this:
While condition
[statements]
End While
Example on While loop
Module Module1
Sub Main()
Dim d, e As Integer
d = 0
e = 6
While e > 4
e -= 1
d += 1
End While
System.Console.WriteLine("The Loop ran " & e & "times")
End Sub
End Module
The image below displays output from above code.
Do Loop
The Do loop can be used to execute a fixed block of statements indefinite number of times. The Do loop keeps executing it's statements while or until the condition is true. Two keywords, while and until can be used with the do loop. The Do loop also supports an Exit Do statement which makes the loop to exit at any moment. The syntax of Do loop looks like this:
Do[{while | Until} condition]
[statements]
[Exit Do]
[statements]
Loop
Example on Do loop
Module Module1
Sub Main()
Dim str As String
Do Until str = "Cool"
System.Console.WriteLine("What to do?")
str = System.Console.ReadLine()
Loop
End Sub
End Module
Do Loop
The Do loop can be used to execute a fixed block of statements indefinite number of times. The Do loop keeps executing it's statements while or until the condition is true. Two keywords, while and until can be used with the do loop. The Do loop also supports an Exit Do statement which makes the loop to exit at any moment. The syntax of Do loop looks like this:
Do[{while | Until} condition]
[statements]
[Exit Do]
[statements]
Loop
Example on Do loop
Module Module1
Sub Main()
Dim str As String
Do Until str = "Cool"
System.Console.WriteLine("What to do?")
str = System.Console.ReadLine()
Loop
End Sub
What is Visual Basic?
Visual Basic is a "visual programming" environment for developing Windows (also Web now) applications. Visual Basic makes it possible to develop complicated applications very quickly. The programmer designs windows graphically, drags program elements from the Visual Basic Toolbox and writes basic code for each element. Visual Basic is "event-driven" which means that procedures are called automatically when the end user chooses menu items, clicks the mouse, moves objects on the screen, etc.
Why is Visual Basic popular?
Programmers have undergone a major change in many years of programming various machines. For example, what could take days to create an application in other programming languages like C, C++ could be done in hours with Visual Basic. Visual Basic provides many interesting sets of tools to aid us in building exciting applications. Visual Basic provides these tools to make our life far more easier because all the real hard code is already written for us.
Visual Basic is not only a programming language but also a true graphical development environment. This environment allows programmers with little programming experience to quickly develop powerful Windows applications. Visual Basic also has the ability to develop programs that can be used as a front-end application to a database system, serving as the user interface which collects user input and displays formatted output in a more appealing and useful form.
Visual Basic is very popular for the ease with which it allows the programmer to create nice looking graphical programs with less coding unlike many other languages that take thousands of lines of programmer keyed code. As the programmer works in the graphical environment much of the program code is automatically generated by the Visual Basic program.
Areas of Use
Using Visual Basic's tools we can quickly translate an abstract idea into a program design that we can actually see on the screen. VB encourages you to experiment, revise, correct, and network your design until the new project meets your requirements. However, most of all, it inspires your imagination and creativity. Visual Basic is ideal for developing applications that run on the Windows operating system. Developing applications with VB can be said to be a 3-step approach:
i) Design the appearance of application
ii) Assign property settings to the objects of the program
iii) Write the code to direct specific tasks at runtime
Visual Basic is used to develop applications in a number of different areas. Some of them are listed below:
* Accounting
* Business
* Commerce
* Consulting
* Education
* Law
* Marketing and Sales
* Medicine
* Research
* Science
Many of the things that we do with Visual Basic really aren’t very basic. The Visual Basic language is powerful, if you can imagine a programming task, it can be accomplished using Visual Basic.
History of Visual Basic
Microsoft first released Visual Basic in 1987. It was the first visual development tool from Microsoft, and it was to compete with C, C++, Pascal and other well-known programming languages. From the start, Visual Basic wasn't a hit. It wasn't until release 2.0 that people really discovered the potential of the language, and with release 3.0 it had become the fastest-growing programming language on the market.
Below is the order and the approximate year in which a new version of Visual Basic was released:
* 1991, VB1 Debuts
* 1992, VB2 Debuts
* 1993, VB3 Debut
* 1996, VB4 Debuts
* 1997, VB5 Debuts
* 1998, VB6 Debuts
* 2001, VB. NET Debuts
for syntax example:
Loops
For Loop
The For loop is the most popular loop. For loops enable us to execute a series of expressions multiple numbers of times. The For loop in VB .NET needs a loop index which counts the number of loop iterations as the loop executes. The syntax for the For loop looks like this:
For index=start to end[Step step]
[statements]
[Exit For]
[statements]
Next[index]
The index variable is set to start automatically when the loop starts. Each time in the loop, index is incremented by step and when index equals end, the loop ends.
Example on For loop
Module Module1
Sub Main()
Dim d As Integer
For d = 0 To 2
System.Console.WriteLine("In the For Loop")
Next d
End Sub
End Module
While loop
While loop keeps executing until the condition against which it tests remain true. The syntax of while loop looks like this:
While condition
[statements]
End While
Example on While loop
Module Module1
Sub Main()
Dim d, e As Integer
d = 0
e = 6
While e > 4
e -= 1
d += 1
End While
System.Console.WriteLine("The Loop ran " & e & "times")
End Sub
End Module
The image below displays output from above code.
Do Loop
The Do loop can be used to execute a fixed block of statements indefinite number of times. The Do loop keeps executing it's statements while or until the condition is true. Two keywords, while and until can be used with the do loop. The Do loop also supports an Exit Do statement which makes the loop to exit at any moment. The syntax of Do loop looks like this:
Do[{while | Until} condition]
[statements]
[Exit Do]
[statements]
Loop
Example on Do loop
Module Module1
Sub Main()
Dim str As String
Do Until str = "Cool"
System.Console.WriteLine("What to do?")
str = System.Console.ReadLine()
Loop
End Sub
End Module
Do Loop
The Do loop can be used to execute a fixed block of statements indefinite number of times. The Do loop keeps executing it's statements while or until the condition is true. Two keywords, while and until can be used with the do loop. The Do loop also supports an Exit Do statement which makes the loop to exit at any moment. The syntax of Do loop looks like this:
Do[{while | Until} condition]
[statements]
[Exit Do]
[statements]
Loop
Example on Do loop
Module Module1
Sub Main()
Dim str As String
Do Until str = "Cool"
System.Console.WriteLine("What to do?")
str = System.Console.ReadLine()
Loop
End Sub
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