VB.NET Array.BinarySearch方法代码示例

Public Class SamplesArray
    Public Shared Sub Main()
        ' Creates and initializes a new Array.
        Dim myIntArray As Array = Array.CreateInstance( GetType(Int32), 5 )

        myIntArray.SetValue( 8, 0 )
        myIntArray.SetValue( 2, 1 )
        myIntArray.SetValue( 6, 2 )
        myIntArray.SetValue( 3, 3 )
        myIntArray.SetValue( 7, 4 )

        ' Do the required sort first
        Array.Sort(myIntArray)

        ' Displays the values of the Array.
        Console.WriteLine("The Int32 array contains the following:")
        PrintValues(myIntArray)

        ' Locates a specific object that does not exist in the Array.
        Dim myObjectOdd As Object = 1
        FindMyObject(myIntArray, myObjectOdd)

        ' Locates an object that exists in the Array.
        Dim myObjectEven As Object = 6
        FindMyObject(myIntArray, myObjectEven)
    End Sub

    Public Shared Sub FindMyObject(myArr As Array, myObject As Object)
        Dim myIndex As Integer = Array.BinarySearch(myArr, myObject)
        If  myIndex < 0 Then
            Console.WriteLine("The object to search for ({0}) is not found. The next larger object is at index {1}.", myObject, Not(myIndex))
        Else
            Console.WriteLine("The object to search for ({0}) is at index {1}.", myObject, myIndex)
        End If
    End Sub

    Public Shared Sub PrintValues(myArr As Array)
        Dim i As Integer = 0
        Dim cols As Integer = myArr.GetLength( myArr.Rank - 1 )
        For Each o As Object In myArr
            If i < cols Then
                i += 1
            Else
                Console.WriteLine()
                i = 1
            End If
            Console.Write( vbTab + "{0}", o)
        Next o
        Console.WriteLine()
    End Sub
End Class

' 导入命名空间
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { _
            "Pachycephalosaurus", _
            "Amargasaurus", _
            "Tyrannosaurus", _
            "Mamenchisaurus", _
            "Deinonychus", _
            "Edmontosaurus"  }

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & "Sort")
        Array.Sort(dinosaurs)

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch for 'Coelophysis':")
        Dim index As Integer = _
            Array.BinarySearch(dinosaurs, "Coelophysis")
        ShowWhere(dinosaurs, index)

        Console.WriteLine(vbLf & _
            "BinarySearch for 'Tyrannosaurus':")
        index = Array.BinarySearch(dinosaurs, "Tyrannosaurus")
        ShowWhere(dinosaurs, index)

    End Sub

    Private Shared Sub ShowWhere(Of T) _
        (ByVal array() As T, ByVal index As Integer) 

        If index < 0 Then
            ' If the index is negative, it represents the bitwise
            ' complement of the next larger element in the array.
            '
            index = index Xor -1

            Console.Write("Not found. Sorts between: ")

            If index = 0 Then
                Console.Write("beginning of array and ")
            Else
                Console.Write("{0} and ", array(index - 1))
            End If 

            If index = array.Length Then
                Console.WriteLine("end of array.")
            Else
                Console.WriteLine("{0}.", array(index))
            End If 
        Else
            Console.WriteLine("Found at index {0}.", index)
        End If

    End Sub

End Class

' 导入命名空间
Imports System.Collections.Generic

Public Class ReverseComparer
    Implements IComparer(Of String)

    Public Function Compare(ByVal x As String, _
        ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        ' Compare y and x in reverse order.
        Return y.CompareTo(x)

    End Function
End Class

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs() As String = { _
            "Pachycephalosaurus", _
            "Amargasaurus", _
            "Tyrannosaurus", _
            "Mamenchisaurus", _
            "Deinonychus", _
            "Edmontosaurus"  }

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Dim rc As New ReverseComparer()

        Console.WriteLine(vbLf & "Sort")
        Array.Sort(dinosaurs, rc)

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch for 'Coelophysis':")
        Dim index As Integer = _
            Array.BinarySearch(dinosaurs, "Coelophysis", rc)
        ShowWhere(dinosaurs, index)

        Console.WriteLine(vbLf & _
            "BinarySearch for 'Tyrannosaurus':")
        index = Array.BinarySearch(dinosaurs, "Tyrannosaurus", rc)
        ShowWhere(dinosaurs, index)

    End Sub

    Private Shared Sub ShowWhere(Of T) _
        (ByVal array() As T, ByVal index As Integer) 

        If index < 0 Then
            ' If the index is negative, it represents the bitwise
            ' complement of the next larger element in the array.
            '
            index = index Xor -1

            Console.Write("Not found. Sorts between: ")

            If index = 0 Then
                Console.Write("beginning of array and ")
            Else
                Console.Write("{0} and ", array(index - 1))
            End If 

            If index = array.Length Then
                Console.WriteLine("end of array.")
            Else
                Console.WriteLine("{0}.", array(index))
            End If 
        Else
            Console.WriteLine("Found at index {0}.", index)
        End If

    End Sub

End Class

' 导入命名空间
Imports System
Imports System.Collections

Public Class MainClass
   Shared Private integerValues As Integer() = {1, 2, 3, 4, 5, 6}

   Shared Private integerValuesCopy(6) As Integer

   Public Shared Sub Main()
      Dim result As Integer

      Console.WriteLine("Initial Array Values:" )
      PrintArray()

      Array.Copy(integerValues, integerValuesCopy,integerValues.Length)

      Console.WriteLine("Array values after Copy:" )

      PrintArray() 

      result = Array.BinarySearch(integerValues, 5)

      If result >= 0 Then
         Console.WriteLine("5 found at element " & result )
      Else
         Console.WriteLine("5 not found" & " in integerValues")
      End If

   End Sub
   Shared Private Sub PrintArray()
      Dim integerElement As Integer

      For Each integerElement In integerValues
         Console.WriteLine(integerElement )
      Next

      Console.WriteLine(" integerValuesCopy: ")

      For Each integerElement In integerValuesCopy
         Console.WriteLine(integerElement )
      Next

   End Sub

End Class