Поменять местами 3 и 8 элементы массива - VB

Private Sub Command1_Click()
Dim Z(1 To 6, 1 To 8) As Single
Dim sum As Single, P As Single
Randomize
For i = 1 To 6
    For j = 1 To 8
        Z(i, j) = Int(10 * Rnd + 1)
    Next j
Next i
P = 1
For i = 1 To 6 Step 2
    For j = 1 To 8
        P = P * Z(i, j)
    Next j
Next i
For i = 2 To 8 Step 2
    For j = 1 To 6
        sum = sum + Z(j, i)
    Next j
Next i
MsgBox "Sum=" & sum & Chr(13) & "Pr=" & P
End Sub
 
Private Sub Command2_Click()
Dim C(1 To 10, 1 To 15) As Single, max As Single
max = -99999999
Randomize
For i = 1 To 10
    For j = 1 To 15
        C(i, j) = Int(100 * Rnd - 50)
        If C(i, j) > max Then max = C(i, j)
    Next j
Next i
MsgBox max
End Sub