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Const BasicCharge As Integer = 25
{{dablink|This article is about the Visual Basic language shipping with Microsoft Visual Studio 6.0 and earlier. For the Visual Basic shipping with Microsoft Visual Studio .NET, see [[Visual Basic .NET]].}}
Dim ExtraCharge As Currency
{{Infobox programming language
Dim Total As Currency
|name = Visual Basic
Private Sub Check1_Click()
|logo = [[Image:VB cover.png|200px|The four colored boxes is the logo of [[Visual Basic for Applications|VBA]], and the two drums above them symbolize database connectivity]]
If Check1.Value = 1 Then
|paradigm = [[Event-driven programming|Event-driven]]
ExtraCharge = ExtraCharge + 3.5
|year =
Else
|designer =
ExtraCharge = ExtraCharge - 3.5
|developer = [[Microsoft]]
End If
|latest_release_version =
Total = BasicCharge + ExtraCharge
|latest_release_date =
Label2.Caption = Total
|typing = [[Type system#Static and dynamic typing|Static]], [[Strongly-typed programming language|strong]]
|implementations =
|dialects =
|influenced_by = [[QuickBASIC]]
|influenced = [[Visual Basic .NET]]
|current version =
|operating_system = [[Microsoft Windows]]
|license =
|website =
}}


End Sub
'''Visual Basic''' ('''VB''') is a [[third-generation programming language|third-generation]] [[event driven programming language]] and associated [[integrated development environment|development environment]] from [[Microsoft]] for its [[Component Object Model|COM]] programming model.<ref>
VB has been deprecated in favor of [[Visual Basic .NET]], although conversion from VB to VB .NET can be non-trivial. [http://msdn.microsoft.com/vbrun/staythepath/additionalresources/upgradingvb6/chapter2.pdf].)
</ref>
Visual Basic was derived from [[BASIC programming language|BASIC]] and enables the [[rapid application development|rapid application development (RAD)]] of [[graphical user interface|graphical user interface (GUI)]] applications, access to [[database]]s using [[Data Access Objects|DAO]], [[Remote Data Objects|RDO]], or [[ActiveX Data Objects|ADO]], and creation of [[ActiveX]] controls and objects. [[Scripting languages]] such as [[Visual Basic for Applications|VBA]] and [[VBScript]] are syntactically similar to Visual Basic, but perform differently.<ref>
For example: <code>S="ABC" : S = S & "DEF" : S = S & "GHI"</code> is common practice in VB, but will cause major problems if used on ASP pages. This is because strings are handled differently by the two languages. The above code will cause significant overhead for VBScript.</ref>


Private Sub Check2_Click()
A programmer can put together an application using the [[software component|components]] provided with Visual Basic itself. Programs written in Visual Basic can also use the [[Windows API]], but doing so requires external function declarations.
If Check2.Value = 1 Then
ExtraCharge = ExtraCharge + 3.5
Else
ExtraCharge = ExtraCharge - 3.5
End If
Total = BasicCharge + ExtraCharge
Label2.Caption = Total


End Sub
In business programming, Visual Basic has one of the largest user bases. In a survey conducted in 2005, 62 percent of developers reported using some form of Visual Basic. It currently competes with [[C++]], [[JavaScript]], [[C sharp|C#]] and [[Java (programming language)|Java]] for dominance in the business world.<ref>http://www.computerworld.com/developmenttopics/development/story/0,10801,100542,00.html</ref>


Private Sub Check3_Click()
==Language features==
If Check3.Value = 1 Then
[[Image:Typical vb6 session.png|thumbnail|300px|An example of a session in Microsoft Visual Basic 6]]
ExtraCharge = ExtraCharge + 3.5
Visual Basic was designed to be easy to learn and use. The language not only allows programmers to create simple [[GUI]] applications, but can also develop fairly complex applications as well.
Else
Programming in VB is a combination of visually arranging [[component]]s or [[control]]s on a [[form]], specifying attributes and actions of those components, and writing additional lines of [[computer code|code]] for more functionality.
ExtraCharge = ExtraCharge - 3.5
Since default attributes and actions are defined for the components, a simple program can be created without the programmer having to write many lines of code.
End If
Performance problems were experienced by earlier versions, but with faster computers and native code compilation this has become less of an issue.
Total = BasicCharge + ExtraCharge
Label2.Caption = Total


End Sub
Although programs can be compiled into native code executables [[#Timeline|from version 5 onwards]], they still require the presence of runtime libraries of approximately 2 MB in size. This runtime is included by default in [[Windows 2000]] and later, but for earlier versions of [[Microsoft Windows|Windows]] it must be distributed together with the executable.


Private Sub Form_Load()
Forms are created using [[drag and drop]] techniques. A tool is used to place controls (e.g., text boxes, buttons, etc.) on the form (window). Controls have [[attribute]]s and [[event handler]]s associated with them. Default values are provided when the control is created, but may be changed by the programmer. Many attribute values can be modified during run time based on user actions or changes in the environment, providing a dynamic application. For example, code can be inserted into the form resize event handler to reposition a control so that it remains centered on the form, expands to fill up the form, etc. By inserting code into the event handler for a keypress in a text box, the program can automatically translate the case of the text being entered, or even prevent certain characters from being inserted.
Total = BasicCharge + ExtraCharge
Label2.Caption = Total


Visual Basic can create executables (EXE files), [[ActiveX Control|ActiveX controls]], DLL files, but is primarily used to develop Windows applications and to interface web database systems. Dialog boxes with less functionality (e.g., no maximize/minimize control) can be used to provide pop-up capabilities. Controls provide the basic functionality of the application, while programmers can insert additional logic within the appropriate event handlers. For example, a drop-down combination box will automatically display its list and allow the user to select any element. An event handler is called when an item is selected, which can then execute additional code created by the programmer to perform some action based on which element was selected, such as populating a related list.

Alternatively, a Visual Basic component can have no user interface, and instead provide ActiveX objects to other programs via [[Component Object Model]] (COM). This allows for [[server-side]] processing or an add-in module.

The language is [[garbage collection (computer science)|garbage collected]] using [[reference counting]], has a large library of utility objects, and has basic [[Object-oriented programming|object oriented support]]. Since the more common components are included in the default project template, the programmer seldom needs to specify additional libraries. Unlike many other programming languages, Visual Basic is generally not case sensitive, although it will transform [[keywords]] into a standard case configuration and force the case of variable names to conform to the case of the entry within the symbol table entry. String comparisons are case sensitive by default, but can be made case insensitive if so desired.

The Visual Basic compiler is shared with other Visual Studio languages (C, C++), but restrictions in the IDE do not allow the creation of some targets (Windows model DLL's) and threading models.

==Characteristics present in Visual Basic==
Visual Basic has the following uncommon traits:
* [[Boolean datatype|Boolean]] constant <tt>True</tt> has numeric value −1.<ref>In most languages, <tt>True</tt> is mapped to a non zero numeric value, often 1 or -1.</ref> This is because the Boolean data type is stored as a 16-bit signed integer. In this construct −1 evaluates to 16 binary 1s (the Boolean value <tt>True</tt>), and 0 as 16 0s (the Boolean value <tt>False</tt>). This is apparent when performing a <tt>Not</tt> operation on a 16 bit signed integer value 0 which will return the integer value −1, in other words <tt>True = Not False</tt>. This [http://vb.mvps.org/tips/Truth.asp inherent functionality] becomes especially useful when performing logical operations on the individual bits of an integer such as <tt>And</tt>, <tt>Or</tt>, <tt>Xor</tt> and <tt>Not</tt>. This definition of <tt>True</tt> is also consistent with BASIC since the early 1970s Microsoft BASIC implementation and is also related to the characteristics of microprocessor instructions at the time.
* Logical and bitwise operators are unified. This is unlike all the C-derived languages (such as [[Java (programming language)|Java]] or [[Perl]]), which have separate logical and bitwise operators. This again is a traditional feature of BASIC.
* Variable [[array]] base. Arrays are declared by specifying the upper and lower bounds in a way similar to Pascal and [[Fortran]]. It is also possible to use the Option Base statement to set the default lower bound. Use of the Option Base statement can lead to confusion when reading Visual Basic code and is best avoided by always explicitly specifying the lower bound of the array. This lower bound is not limited to 0 or 1, because it can also be set by declaration. In this way, both the lower and upper bounds are programmable. In more subscript-limited languages, the lower bound of the array is not variable. This uncommon trait does not exist in [[Visual Basic .NET]] and [[VBScript]].
: OPTION BASE was introduced by ANSI, with the standard for ANSI Minimal BASIC in the late 1970s. The extension to using a form of DIM A(1976 TO 2020) was first introduced in [[BBC Basic]], found on the [[BBC micro]], which in turn was influenced by [[COMAL]].
* Relatively strong integration with the [[Windows operating system]] and the [[Component Object Model]].
* [[Rounding#Round-to-even method|Banker's rounding]] as the default behavior when converting real numbers to integers.
* Integers are automatically promoted to reals in expressions involving the normal division operator (<tt>/</tt>) so that division of an odd integer by an even integer produces the intuitively correct result. There is a specific integer divide operator (<tt>\</tt>) which does truncate.
* By default, if a variable has not been declared or if no type declaration character is specified, the variable is of type <tt>[[Variant type|Variant]]</tt>. However this can be changed with Deftype statements such as <tt>DefInt</tt>, <tt>DefBool</tt>, <tt>DefVar</tt>, <tt>DefObj</tt>, <tt>DefStr</tt>. There are 12 <tt>Deftype</tt> statements in total offered by Visual Basic 6.0. The default type may be overridden for a specific declaration by using a special suffix character on the variable name (<tt>#</tt> for Double, <tt>!</tt> for Single, <tt>&</tt> for Long, <tt>%</tt> for Integer, <tt>$</tt> for String, and <tt>@</tt> for Currency) or using the key phrase <tt>As (type)</tt>. VB can also be set in a mode that only explicitly declared variables can be used with the command <tt>Option Explicit</tt>.



==Evolution of Visual Basic==
VB 1.0 was introduced in [[1991]]. The approach for connecting the programming language to the graphical user interface is derived from a prototype developed by [[Alan Cooper]] called ''Tripod''. Microsoft contracted with Cooper and his associates to develop Tripod into a programmable shell for Windows 3.0, under the code name ''Ruby'' (no relation to the [[Ruby programming language]]).

Tripod did not include a programming language at all, and Ruby contained only a rudimentary command processor sufficient for its role as a Windows shell. Microsoft decided to use the simple [[Program Manager]] shell for Windows 3.0 instead of Ruby, and combine Ruby with the Basic language to create Visual Basic.

Ruby provided the "visual" part of Visual Basic — the form designer and editing tools — along with the ability to load [[dynamic link library|dynamic link libraries]] containing additional controls (then called "gizmos"). Ruby's extensible gizmos later became the [[VBX]] interface.

===Timeline of Visual Basic (VB1 to VB6)===
* Project 'Thunder' was initiated
* Visual Basic 1.0 (May [[1991]]) was released for Windows at the Comdex/Windows World trade show in Atlanta, Georgia.
[[Image:VBDOS-icon.PNG|right|VB DOS Logo]]
[[Image:Microsoft Visual Basic for MS-DOS (Professional Edition Version1.00).png|thumb|right|300px|Visual Basic for MS-DOS]]
* Visual Basic 1.0 for [[DOS]] was released in September [[1992]]. The language itself was not quite compatible with Visual Basic for Windows, as it was actually the next version of Microsoft's DOS-based BASIC compilers, [[Microsoft QuickBASIC compiler|QuickBASIC]] and BASIC Professional Development System. The interface was textual, using [[extended ASCII]] characters to simulate the appearance of a [[GUI]].
* Visual Basic 2.0 was released in November [[1992]]. The programming environment was easier to use, and its speed was improved. Notably, forms became instantiable objects, thus laying the foundational concepts of class modules as were later offered in VB4.
* Visual Basic 3.0 was released in the summer of [[1993]] and came in Standard and Professional versions. VB3 included version 1.1 of the [[Microsoft Jet Database Engine]] that could read and write Jet (or Access) 1.x databases.
* Visual Basic 4.0 (August [[1995]]) was the first version that could create [[32-bit]] as well as [[16-bit]] Windows programs. It also introduced the ability to write non-GUI classes in Visual Basic.
* With version 5.0 (February [[1997]]), Microsoft released Visual Basic exclusively for [[32-bit]] versions of Windows. Programmers who preferred to write 16-bit programs were able to import programs written in Visual Basic 4.0 to Visual Basic 5.0, and Visual Basic 5.0 programs can easily be converted with Visual Basic 4.0. Visual Basic 5.0 also introduced the ability to create custom user controls, as well as the ability to compile to native Windows executable code, speeding up calculation-intensive code execution.
* Visual Basic 6.0 (Mid [[1998]]) improved in a number of areas, including the ability to create web-based applications. VB6 is currently scheduled to enter Microsoft's "non-supported phase" starting March [[2008]].
* Mainstream Support for Microsoft Visual Basic 6.0 ended on [[March 31]], [[2005]]. Extended support will end in March 2008.<ref>http://msdn2.microsoft.com/en-us/vbrun/ms788707.aspx</ref> In response, the Visual Basic user community expressed its grave concern and lobbied users to sign a petition to keep the product alive.<ref>http://www.classicvb.org/petition/</ref> Microsoft has so far refused to change their position on the matter. Ironically, around this time, it was exposed that Microsoft's new anti-spyware offering, [[Microsoft AntiSpyware]] (part of the [[GIANT Company Software]] purchase), was coded in Visual Basic 6.0.<ref>{{cite web| url=http://www.theregister.co.uk/2005/07/22/microsoft_spyware_vb6/| title = MS Anti-Spyware built on MS Abandonware | The Register| accessdate = 2006-10-04| publisher = The Register| author = Andrew Orlowski and Carey Bishop | year = [[2005-07-22]]}}</ref> Windows Defender Beta 2 was rewritten as C++/CLI code.<ref>http://www.winsupersite.com/reviews/windefender_beta2.asp</ref> It is difficult to tell what impact this decision will have on any future offerings of Microsoft if the perception is created that long lasting applications cannot be built with Microsoft Products due to [[planned obsolescence]].{{Fact|date=September 2007}}

==Derivative languages==
[[Microsoft]] has developed derivatives of Visual Basic for use in [[Scripting language|scripting]]. It is derived heavily from [[BASIC programming language|BASIC]] and host [[Application software|applications]], and has replaced the original Visual Basic language with a [[.NET Framework|.NET]] platform version:
* [[Visual Basic for Applications]] (VBA) is included in many Microsoft applications ([[Microsoft Office]]), and also in many third-party products like [[AutoCAD]], [[WordPerfect Office|WordPerfect Office 2002]] and [[ArcGIS]]. There are small inconsistencies in the way VBA is implemented in different applications, but it is largely the same language as VB6 and uses the same runtime library.
* [[VBScript programming language|VBScript]] is the default language for [[Active Server Pages]] and can be used in [[Microsoft Windows|Windows]] scripting and client-side [[web page]] scripting. Although it resembles VB in syntax, it is a separate language and it is executed by the [[Windows Script Host]] as opposed to the VB runtime. These differences can affect the performance of an ASP web site. ASP and VBScript must not be confused with [[ASP.NET]] which uses Visual Basic.NET or any other language that targets the .NET [[Common Language Runtime]].
* [[Visual Basic .NET]] is Microsoft's designated successor to Visual Basic 6.0, and is part of Microsoft's [[.NET Framework|.NET]] platform. It compiles and runs on the .NET Framework. It is not [[backwards compatible]] with VB6. An automated conversion tool exists, but for some projects automated conversion is impossible.<ref>{{cite web
|url = http://www.devx.com/vb/article/16822
|title = Abandoning the Fantasy of VB Migration Wizardry
|accessdate = 2007-05-17
|last = Piquet
|first = Lori
|date = [[2002-02-20]]
|work = DevX.com
|publisher = Jupitermedia
}}</ref>

==Performance and other issues==
Earlier counterparts of Visual Basic (prior to version 5) compiled the code to [[P-Code]] or Pseudo code only. Visual Basic 5 and 6 are able to compile the code to either native or P-Code as the programmer chooses. The P-Code is interpreted by the language runtime, also known as virtual machine, implemented for benefits such as portability and small code. However, it usually slows down the execution by adding an additional layer of interpretation of code by the runtime although small amounts of code and algorithms can be constructed to run faster than the compiled native code. Visual Basic applications require Microsoft Visual Basic runtime MSVBVMxx.DLL, where xx is the relevant version number, either 50 or 60. MSVBVM60.dll comes as standard with Windows in all editions after Windows 98 while MSVBVM50.dll comes with all editions after Windows 95. A Windows 95 machine would however require that which ever dll was needed by the program was included with the installer.

Visual Basic is criticized for its poor memory management and non-standard programming constructs which is said to result in poor programming practices and inefficient outputs. When programming in Visual Basic, it can sometimes be hard to tell if a variable is a reference to an object, or is the explicit object. In the same vein, it can sometimes be difficult to tell if an operation will result in a copy of a reference to an object, or a copy of the entire object. This ambiguity could result in unexpected results or poor program performance.

==Sample code==
Here are some examples of the language:
<!-- Please don't add any sample code before discussing it on the talk page -->

'''Function that returns the area of a circle:'''
<source lang="vb">
Private Function AreaOfCircle(Radius As Double) As Double
Const PI = 3.14159265358979323846264 (This can also be math.PI)
AreaOfCircle = PI * (Radius ^ 2)
End Function
</source>
'''Program to display a pop-up window with the words "Hello World" on it:'''
<source lang="vb">
Sub Main()
MsgBox "Hello World"
End Sub
End Sub
</source>

==See also==
<div style="-moz-column-count:2; column-count:2;">
* [[Microsoft Visual Studio Express]]
* [[Visual Basic 6 to .NET Function Equivalents]]
* [[Comparison of programming languages]]
* CodeSMART a software productivity product that extends the classic Visual Basic IDE.
* [[BlitzMAX]] &ndash; A programming language with a more properly object oriented dialect, compared to Visual Basic
* [[IIf]] &ndash; a function in several editions of Visual Basic that returns one of its two parameters based on the evaluation of an expression. Similar to a conditional statement, or roughly equivalent to the [[?:]] ternary operator of C and related languages.
* [[Properties window]]
* [[Gambas]] &ndash; Visual Basic like programming tool for Unix systems.
* [[Visual Basic .NET]]
</div>

==References==
<references />

==External links==
{{wikibooks|Programming:Visual Basic Classic}}
*[http://brandinimp.com/vbbasics1/ BrandiniMP's Guide to Visual Basic 6] – The basics of Visual Basic 6
*[http://msdn.microsoft.com/vbrun/default.aspx VB 6.0 at MSDN]
*[http://www.cooper.com/alan/father_of_vb.html "The Father of Visual Basic"] – History of the "Visual" part of Visual Basic
*{{dmoz|Computers/Programming/Languages/Visual_Basic/|Visual Basic}}
*[http://support.microsoft.com/default.aspx?scid=kb;EN-US;q196286 Visual Basic runtime libraries] – these are needed by Visual Basic programs to run; you can download them from Microsoft if they don't ship with the program.
<!-- Please don't add any links to freetuts or any of its clones -->

{{BASIC}}

[[Category:Programming languages]]
[[Category:Procedural programming languages]]
[[Category:Microsoft BASIC]]
[[Category:Microsoft Visual Studio|Basic]]
[[Category:Microsoft development tools]]

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Revision as of 18:01, 5 December 2007

Const BasicCharge As Integer = 25 Dim ExtraCharge As Currency Dim Total As Currency Private Sub Check1_Click() If Check1.Value = 1 Then 

   ExtraCharge = ExtraCharge + 3.5

Else 

   ExtraCharge = ExtraCharge - 3.5

End If Total = BasicCharge + ExtraCharge Label2.Caption = Total

End Sub

Private Sub Check2_Click() If Check2.Value = 1 Then 

   ExtraCharge = ExtraCharge + 3.5

Else 

   ExtraCharge = ExtraCharge - 3.5

End If Total = BasicCharge + ExtraCharge Label2.Caption = Total

End Sub

Private Sub Check3_Click() If Check3.Value = 1 Then 

   ExtraCharge = ExtraCharge + 3.5

Else 

   ExtraCharge = ExtraCharge - 3.5

End If Total = BasicCharge + ExtraCharge Label2.Caption = Total

End Sub

Private Sub Form_Load() Total = BasicCharge + ExtraCharge Label2.Caption = Total

End Sub

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