[Year 12 SofDev] Binary search example?

[Kevork Krozian]

Dear Chris,

 On more times than I can remember you have quickly arrived to the rescue
of colleagues who need something ( advice, solution, validation,
references etc. ) really quickly in either current or recent programming
developments in VB and its variants.
 On behalf of all who have and continue to benefit from your enormous
knowledge in the area --  thank you !

Kevork




> Hi Trav,
>
> Try this on for size, it is based on code from the book "Data Structures
> and Algorithms Using Visual Basic.NET" by Michael McMillan
>
> Regards Chris
>
>
> [cid:image001.png at 01CC2B72.39F67120]
>
>
>
>
> Module Module1
>     Const ARRAY_SIZE As Integer = 9 'i.e. 10 item can be stored in the
> array - VB.NET has zero indexed arrays
>     Dim arr(ARRAY_SIZE) As Integer
>
>     Sub Main()
>         'Fill array with random numbers
>         For index As Integer = 0 To ARRAY_SIZE
>             arr(index) = (CInt(Int(100 * Rnd() + 1)))
>         Next
>         'Sort array
>         SelectionSort()
>         'Show sorted array
>         showArray()
>
>         'Find number 77 in array using standard Binary Search
>         Dim position As Integer = binSearch(77)
>         If (position > -1) Then
>             Console.WriteLine("77 found at position " & position.ToString)
>         Else
>             Console.WriteLine("Not in the array.")
>         End If
>
>         'Find number 77 in array using standard Binary Search
>         position = RecursiveBinSearch(77, 0, ARRAY_SIZE)
>         If (position > -1) Then
>             Console.WriteLine("77 found at position " & position.ToString)
>         Else
>             Console.WriteLine("Not in the array.")
>         End If
>         Console.Read()
>
>     End Sub
>
>     Public Function binSearch(ByVal value As Integer) As Integer
>         Dim upperBound, lowerBound, mid As Integer
>         upperBound = ARRAY_SIZE 'arr.GetUpperBound(0)
>         lowerBound = 0
>         While (lowerBound <= upperBound)
>             mid = (upperBound + lowerBound) \ 2
>             If (arr(mid) = value) Then
>                 Return mid
>             ElseIf (value < arr(mid)) Then
>                 upperBound = mid - 1
>             Else
>                 lowerBound = mid + 1
>             End If
>         End While
>         Return -1
>     End Function
>
>     Public Function RecursiveBinSearch(ByVal value As Integer, ByVal lower
> As Integer, ByVal upper As Integer) As Integer
>         If (lower > upper) Then
>             Return -1
>         Else
>             Dim mid As Integer
>             mid = (upper + lower) \ 2
>             If (value < arr(mid)) Then
>                 RecursiveBinSearch(value, lower, mid - 1)
>             ElseIf (value = arr(mid)) Then
>                 Return mid
>             Else
>                 Return RecursiveBinSearch(value, mid + 1, upper)
>             End If
>         End If
>     End Function
>
>     Public Sub SelectionSort()
>         Dim outer, inner, min, temp As Integer
>         For outer = 0 To ARRAY_SIZE - 1
>             min = outer
>             For inner = outer + 1 To ARRAY_SIZE
>                 If (arr(inner) < arr(min)) Then
>                     min = inner
>                 End If
>             Next
>             temp = arr(outer)
>             arr(outer) = arr(min)
>             arr(min) = temp
>         Next
>     End Sub
>
>     Public Sub showArray()
>         Dim index As Integer
>         For index = 0 To ARRAY_SIZE
>             Console.Write(arr(index) & " ")
>         Next
>         Console.WriteLine()
>     End Sub
>
> End Module
>
>
> From: sofdev-bounces at edulists.com.au
> [mailto:sofdev-bounces at edulists.com.au] On Behalf Of Travis Parker
> Sent: Wednesday, 15 June 2011 2:47 PM
> To: Year 12 Software Development Teachers' Mailing List
> Subject: [Year 12 SofDev] Binary search example?
>
> Dear All,
>
> I was just wondering if anyone has a VB program (Using dot net 2010) that
> uses a binary search? I would ideally like to give the class a simple
> program to demonstrate it in action, and rather than write one from
> scratch during the exam/reporting time - I'm sure one of my more learned
> colleagues would have one lying around!
>
> Cheers
>
> Trav
>
>
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