Bu program vasıtası ile KDV hesaplamayı öğrenmeye ne dersiniz?

Public Class Form1
    Dim mik As Integer
    Dim a, hesap As Integer
    Dim d As Integer
    Dim b As Integer
    Dim c As Integer

    Private Sub TekstilToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TekstilToolStripMenuItem.Click
        c = InputBox("kdv oranını giriniz")
    End Sub

    Private Sub MeyveToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MeyveToolStripMenuItem.Click
        b = InputBox("kdv oranını giriniz")
    End Sub

    Private Sub GıdaToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles GıdaToolStripMenuItem.Click
        d = InputBox("kdv oranını giriniz")
    End Sub

    Private Sub Button1_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        mik = TextBox1.Text

        If ComboBox1.Text = "tekstil" Then
            hesap = (mik * (c / 100)) + mik
            TextBox2.Text = hesap
        ElseIf ComboBox1.Text = "gıda" Then
            hesap = (mik * (d / 100)) + mik
            TextBox2.Text = hesap
        ElseIf ComboBox1.Text = "meyve" Then
            hesap = (mik * (b / 100)) + mik
            TextBox2.Text = hesap
        End If
    End Sub
End Class