Imports System
Imports System.Collections.Generic
Public Class Program
Public Shared Sub reverseOddIndexes(ByVal arr As Integer())
Dim stack As Stack(Of Integer) = New Stack(Of Integer)()
For i As Integer = 1 To arr.Length - 1 Step 2
stack.Push(arr(i))
Next
For i As Integer = 1 To arr.Length - 1 Step 2
arr(i) = stack.Pop()
Next
End Sub
Public Shared Sub Main(ByVal args As String())
Dim arr As Integer() = New Integer() {-1, 9, -1, 0, -1, 7, -1, 5}
Console.WriteLine(String.Join(" "c, arr))
reverseOddIndexes(arr)
Console.WriteLine(String.Join(" "c, arr))
End Sub
End Class
' run:
'
' -1 9 -1 0 -1 7 -1 5
' -1 5 -1 7 -1 0 -1 9
'