VB.Net Tutorial/Collections/Array Sort Reverse

Array.BinarySearch

Imports System.Collections
Public Class Tester
   Shared Sub Main()
      Dim integerValues As Integer() = {1, 2, 3, 4, 5, 6}
      Dim integerElement As Integer
      For Each integerElement In integerValues
         Console.WriteLine(integerElement)
      Next
      Dim result As Integer = Array.BinarySearch(integerValues, 5)
      If result >= 0 Then
         Console.WriteLine("5 found at element " & result &" in integerValues")
      Else
         Console.WriteLine("5 not found" & " in integerValues")
      End If
   End Sub
End Class

1
2
3
4
5
6
5 found at element 4 in integerValues

Array Reverse and Sort

Option Strict On
 Imports System
 Class Tester
     Public Shared Sub DisplayArray(ByVal theArray( ) As Object)
         Dim obj As Object
         For Each obj In theArray
             Console.WriteLine("Value: {0}", obj)
         Next obj
         Console.WriteLine(ControlChars.Lf)
     End Sub 
     Public Shared Sub Main( )
         Dim myArray As [String]( ) = {"W", "s", "J", "t"}
         Console.WriteLine("Display myArray...")
         DisplayArray(myArray)
         Console.WriteLine("Reverse and display myArray...")
         Array.Reverse(myArray)
         DisplayArray(myArray)
         Dim myOtherArray As [String]( ) ={"W", "d", "e", "s", "o", "e", "f", "t"}
         Console.WriteLine("Display myOtherArray...")
         DisplayArray(myOtherArray)
         Console.WriteLine("Sort and display myOtherArray...")
         Array.Sort(myOtherArray)
         DisplayArray(myOtherArray)
     End Sub "Main
 End Class "Tester

Display myArray...
Value: W
Value: s
Value: J
Value: t

Reverse and display myArray...
Value: t
Value: J
Value: s
Value: W

Display myOtherArray...
Value: W
Value: d
Value: e
Value: s
Value: o
Value: e
Value: f
Value: t

Sort and display myOtherArray...
Value: d
Value: e
Value: e
Value: f
Value: o
Value: s
Value: t
Value: W

Array.Sort and Array.IndexOf

Imports System.Collections

public class Test
   public Shared Sub Main
        Dim StringArray() As String = {"This", "is", "a", "test"}
        Dim E As IEnumerator = StringArray.GetEnumerator()
    
        While (E.MoveNext())
          Console.WriteLine(E.Current())
        End While
    
        Dim NewArray(StringArray.Length) As String
        Array.Copy(StringArray, NewArray, StringArray.Length)
    
        Console.WriteLine(Array.IndexOf(NewArray, "a"))
   End Sub
End class

This
is
a
test
2

Demonstrating binary search of an array

Public Class Tester
    Dim Shared array1 As Integer() = New Integer(14) {}
    Public Shared Sub Main
      Dim i As Integer
      For i = 0 To array1.GetUpperBound(0)
         array1(i) = 2 * i
      Next
      Dim searchKey As Integer = 8
      Dim element As Integer = BinarySearch(array1, searchKey)
      If element <> -1 Then
         Console.WriteLine("Found value in element " & element)
      Else
         Console.WriteLine("Value not found")
      End If

    End Sub
   " performs binary search
   Shared Function BinarySearch(ByVal array As Integer(), _
      ByVal key As Integer) As Integer
      Dim low As Integer = 0                 " low index
      Dim high As Integer = array.GetUpperBound(0) " high index 
      Dim middle As Integer             " middle index
      While low <= high
         middle = (low + high) \ 2
         If key = array(middle) Then     " match
            Return middle
         ElseIf key < array(middle) Then " search low end
            high = middle - 1            " of array
         Else
            low = middle + 1
         End If
      End While
      Return -1 " search key not found
   End Function " BinarySearch
End Class

Found value in element 4

Linear search of an array

Public Class Tester
    Public Shared Sub Main
    
      Dim array1 As Integer() = New Integer(19) {}
      Dim randomNumber As Random = New Random()
      Dim i As Integer
      " creates string containing 11 random numbers
      For i = 0 To array1.GetUpperBound(0)
         array1(i) = randomNumber.Next(1000)
         Console.Write ( array1(i) & " ")
      Next
      Console.WriteLine("")

      Dim searchKey As Integer = 12
      Dim element As Integer = LinearSearch(searchKey, array1)
      If element <> -1 Then
         Console.WriteLine("Found Value in index " & element)
      Else
         Console.WriteLine("Value Not Found")
      End If
    End Sub
    Shared Function LinearSearch(ByVal key As Integer, _
      ByVal numbers As Integer()) As Integer
      Dim n As Integer
      " structure iterates linearly through array
      For n = 0 To numbers.GetUpperBound(0)
         If numbers(n) = key Then
            Return n
         End If
      Next
      Return -1
   End Function " LinearSearch
End Class

269 875 968 591 930 801 98 760 596 715 433 655 902 602 257 186 470 856 277 109
Value Not Found

Reverse the contents of an array

Public Class Tester
    Public Shared Sub Main
    
        Dim arrayReverse() As String = {"A", "B", "C", "D", "E"}
        For Each fruit As String In arrayReverse
            Console.WriteLine(fruit)
        Next fruit
        Array.Reverse(arrayReverse)
        For Each fruit As String In arrayReverse
            Console.WriteLine(fruit)
        Next fruit
    End Sub
End Class

A
B
C
D
E
E
D
C
B
A