Program Kontrol Perulangan pada VB NET

Public Class Form1

    Dim a As Integer

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        ListBox1.Items.Clear()

        For a = 1 To 100

            ListBox1.Items.Add(a)

        Next

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

        ListBox1.Items.Clear()

        For a = 100 To 1 Step -2

            ListBox1.Items.Add(a)

        Next

    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

        ListBox1.Items.Clear()

        a = Asc("A")

        Do Until a > Asc("Z")

            ListBox1.Items.Add("huruf :" & Chr(a))

            a = a + 1

        Loop

    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click

        ListBox1.Items.Clear()

        a = Asc("Z")

        Do While a >= Asc("A")

            ListBox1.Items.Add("huruf :" & Chr(a))

            a = a - 1

        Loop

    End Sub

End Class

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