Imports System
Imports System.Collections.Generic
Module AlphabetRangoli
Sub PrintAlphabetRangoli(n As Integer)
If n <= 0 Then Return
' Total width of the grid based on character and hyphen spacing
Dim totalWidth As Integer = 4 * n - 3
' Loop from -(n-1) to (n-1) to leverage geometric symmetry
For i As Integer = -(n - 1) To (n - 1)
Dim currentRowDist As Integer = Math.Abs(i)
Dim lineChars As New List(Of String)()
Dim maxChars As Integer = n - currentRowDist
' 1. Build the left/descending side of characters
For j As Integer = 0 To maxChars - 1
Dim targetChar As Char = Convert.ToChar(Convert.ToInt32("a"c) + n - 1 - j)
lineChars.Add(targetChar.ToString())
Next
' 2. Build the right/ascending side of characters
For j As Integer = maxChars - 2 To 0 Step -1
Dim targetChar As Char = Convert.ToChar(Convert.ToInt32("a"c) + n - 1 - j)
lineChars.Add(targetChar.ToString())
Next
' 3. Interleave hyphens between characters
Dim formattedRow As String = String.Join("-", lineChars)
' 4. Calculate hyphen padding on each side and print
Dim paddingSize As Integer = (totalWidth - formattedRow.Length) \ 2
Dim sideHyphens As New String("-"c, paddingSize)
Console.WriteLine(sideHyphens & formattedRow & sideHyphens)
Next
End Sub
Sub Main()
Dim n As Integer = 5
PrintAlphabetRangoli(n)
End Sub
End Module
' run:
'
' --------e--------
' ------e-d-e------
' ----e-d-c-d-e----
' --e-d-c-b-c-d-e--
' e-d-c-b-a-b-c-d-e
' --e-d-c-b-c-d-e--
' ----e-d-c-d-e----
' ------e-d-e------
' --------e--------
'
