для вектора а(7) найти произведение и количество элементов на четных местах (бейсик)

[JRey]

Здравствуйте, помогите пожалуйста решить задание, прикреплю свой код и форму
язык - Visual Basic, МАССИВ!

Public Class Form2
    Dim s As Double
    Dim a() As Double
    Dim n As Integer
    

    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Dim i As Integer
        n = 7
        ReDim a(n - 1)
        Randomize()
        For i = 0 To n - 1
            a(i) = Val(Format("999", 7 * Rnd()))
            ListBox1.Items.Add(Str(a(i)))
        Next i
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim a(7) As Integer
        Dim n
        s = 1
        For i = 1 To 7
            If i Mod 2 = 0 Then
                n = n + 1
                s = s * a(i)
            End If

        Next i
        TextBox2.Text = n
        TextBox1.Text = s
    End Sub
End Class