В заданной матрице переставить местами столбцы - VB

Private Sub Command1_Click()
Dim a(1 To 3, 1 To 4) As Integer
Dim max As Integer
Dim k As Integer
Dim s As Integer
s = InputBox("Введите номер столбца 1-4")
Randomize
For i = 1 To 3
    Print
    For j = 1 To 4
        a(i, j) = Int(Rnd * 10) + 1
        Print a(i, j);
    Next j
Next i
 
max = a(1, 1)
Print
For i = 1 To 3
    For j = 1 To 4
      If a(i, j) > max Then
            max = a(i, j)
            k = j
      End If
      
    Next j
Next i
Dim tmp As Integer
Print "Новая матрица"
For i = 1 To 3
    Print
    For j = 1 To 4
     If j = s Then
        tmp = a(i, j)
        a(i, j) = a(i, k)
        a(i, k) = tmp
    End If
     
           
        Print a(i, j);
    Next j
Next i
 
End Sub