' ------------------------------------------------------------
' A small program demonstrating how to remove every Nth element
' from a List(Of T) using clear, expressive VB.NET patterns.
' ------------------------------------------------------------
Imports System
Imports System.Collections.Generic
Module Program
'
' This function returns a new list with every Nth element removed.
'
' It performs a single pass over the input list. VB.NET lists use
' zero‑based indexing, so we check (index + 1) Mod n <> 0 to keep
' elements that are *not* in the Nth position.
'
' The variable "size" captures the list length before the loop,
' which avoids repeatedly accessing items.Count inside the loop.
'
Function RemoveEveryNth(Of T)(items As List(Of T), n As Integer) As List(Of T)
If n <= 0 Then
Throw New ArgumentException("n must be a positive integer")
End If
Dim result As New List(Of T)(items.Count)
Dim size As Integer = items.Count ' capture size once
For i As Integer = 0 To size - 1
If (i + 1) Mod n <> 0 Then
result.Add(items(i))
End If
Next
Return result
End Function
'
' Keeping Main small and focused makes the program easy to extend.
' Here we demonstrate the function with a simple example.
'
Sub Main()
Dim data As New List(Of Integer)
For i As Integer = 1 To 20
data.Add(i) ' Example list: numbers 1–20
Next
Dim n As Integer = 3 ' Remove every 3rd element
Dim cleaned As List(Of Integer) = RemoveEveryNth(data, n)
Console.WriteLine("Original: " & String.Join(" ", data))
Console.WriteLine("After removing every " & n & "-th element: " &
String.Join(" ", cleaned))
End Sub
End Module
'
' run:
'
' Original: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
' After removing every 3-th element: 1 2 4 5 7 8 10 11 13 14 16 17 19 20
'
