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Thursday, 15 September 2016

Introduction to Visual Basic.( Topic Top #1 in Top #10)

A very Informative Topic Top #1 in top #10

Visual Basic

Visual Basic:

Visual Basic is a language that is very easy in learning and also in coding. Visual Basic known as (VB). It is a programming environment presented from Microsoft in which a programmer uses a graphical user interface (GUI) to choose and modify preselected sections of code written in the BASIC abbreviated as (Beginner's All-Purpose Symbolic Instruction Code) programming language.


Topic Contents
::Introduction
::Problem Domain
::Problem Domain (ctd.)
::History and Evalution
::Compare to C# & Java
::Comparison to VBScript
::VB.Net Language Concept
::Bubble Sort Using VB (Program Source Code)
::Verification of Data Example
::Array Code Examples

Problem Domain
Visual Basic was derived from BASIC. It enables rapid application development of GUI applications, access to databases, and creation of ActiveX controls and objects. Microsoft stopped supporting Visual Basic in 2005, focusing on Visual Basic .NET. Because they wanted them to online eligibility of it

Problem Domain (ctd.)
Visual Basic.NET is an evolution of Visual Basic, implemented on the Microsoft .NET framework. Because of the .NET architecture earlier versions of Visual Basic had to be re-written before they could be used with .NET. Visual Basic.NET dropped the .NET from it’s name in Visual Basic 2005. So Vista will run Visual Basic 6 programs, but Microsoft does not sell Visual Basic 6 anymore.  They are encouraging users to switch to VB.NET.
History and Evolution
Visual Basic 1.0 for DOS was released in September 1992. The interface was textual, using extend ASCII characters to simulate the appearance of a GUI. Visual Basic 2.0 was released in November 1992. Here the programming environment was easier to use, and its speed was improved. Visual Basic 3.0 was released in the summer of 1993 and came in Standard and Professional versions. 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. Visual Basic 5.0 (February 1997), Microsoft released Visual Basic exclusively for 32-bit versions of Windows. Visual Basic 6.0 (Mid 1998) improved in a number of areas, including the ability to create web-based applications. Visual Basic .NET (2002) (VB7) – Microsoft released VB.NET along with C# which received most of the attention. Visual Basic .NET (2003) (VB 7.1) – Improvements were made in the performance and reliability of the .NET IDE
Visual Basic 2005 (VB 8.0) – Microsoft dropped the .NET portion of the title.  Many improvements were made to reinforce Visual Basic .NET as a rapid application development platform and further differentiate it from C#. Visual Basic 2008 (VB 9.0) – released with the Microsoft .NET Framework 3.5 on November 19, 2007.  Release included:

  Ø  True ternary operator If(boolean, value, value) to replace IIF function 
  Ø  Lambda expressions
  Ø  XML Literals
  Ø  Type Interface

Compared to C# and Java
`
C# AND Java

Virtual Basic
int i;
double d;
String s;
dim i As Integer
dim d As Double
dim s As String
if(a == b){
       //Code
}
else{
       //Code
}
if a = b then
       ‘Code
else
       ‘Code
end if
public class Hello{
       //Code
}
Public Class Hello
       ‘Code
End Class

Comparison to VBScript
Visual Basic is a Windows based programming language for individually running applications while VBScript is a scripting language mainly used to design web sites. Because of the way the purposes of these languages, Visual Basic can be written in an environment that aids in implementation whereas VBScript can only be written in a plain text file with no support.
VB.NET Language Concepts
Ø  Uses Me instead of this
Ø  Does not use a ; for initialization
Ø  Used as a code behind for ASP.NET
Ø  Does not use standard escapes characters
Ø  Sub same as a function
Ø  Partial Classes

Bubble Sort Using VB
Sub bubblesort(ByRef need(), max_min As Boolean)
        Dim now As Integer                                                        
        Dim never As Boolean                                                        
        Dim pick As Integer: pick = UBound(need)                                   
        Dim lower As Integer: lower = LBound(need)
          For i = lower To pick
               For j = lower To pick – 1
                    If need(j) > need(j + 1) = Not max_min Then                    
now = need(j): need(j) = need(j + 1): need(j + 1) = now
                         never = True                                               
                    End If
               Next j
                If never = False Then Exit Sub Else never = False
          Next i
     End Sub
Verification of Data Example
Private Sub Emp_Name_AfterUpdate()
If Nz(DLookup("Emp_Name", "Employees", _ "Emp_Name='" & Me.Emp_Name & "'"), "zzzz") <> _ "zzzz" Then MsgBox & _
"That name already exists in the employee table.“
End Sub
Array Code Examples
Dim strData()  As String = {"Joe Hasterman", "Ted Mattison", "Joe Rummel", "Brian _ Gurnure", "Doug Landal"}
Dim strMatrix(,) As String = {{"Red", "Green"}, {"Yellow", "Purple"}, {"Blue", "Orange"}}
Dim strMatrix(6) As String
strArray(0) = “Hello”
strArray(1) = “Help”
strArray(2) = “Hangover”
strArray(3) = “Happened”
strArray(4) = “Headache”

strArray(5) = “Aspirin”

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