Public Class MicrowaveOven
   Private timeString As String = _
      String.Empty ' contains time entered as a String
   Private cookTime As Time ' holds the time

   ' event handler appends 1 to time string
   Private Sub oneButton_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles oneButton.Click
      Beep() ' sound beep
      timeString &= "1" ' append digit to time input
      DisplayTime() ' display time input properly
   End Sub ' oneButton_Click

   ' event handler appends 2 to time string
   Private Sub twoButton_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles twoButton.Click
      Beep() ' sound beep
      timeString &= "2" ' append digit to time input
      DisplayTime() ' display time input properly
   End Sub ' twobutton_Click

   'Add buttons 3 - 9 and 0...



   ' event handler starts the microwave oven's cooking process
   Private Sub startButton_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles startButton.Click
      Beep()
      timeString = String.Empty ' clear timeString for future input
      clockTimer.Enabled = True ' begin timer
      windowLabel.BackColor = Color.Yellow ' turn "light" on
   End Sub ' startButton_Click

   ' event handler to clear input
   Private Sub clearButton_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles clearButton.Click

      ' Add code to reset each method or variable to its initial setting
     
   End Sub ' clearButton_Click

   ' method to display formatted time in timer window
   Private Sub DisplayTime()
      Dim second As Integer
      Dim minute As Integer
      Dim hour As Integer
      Dim time As String ' the display String

      ' disallow extra input if number of hours > 9
      If timeString.Length > 5 Then
         ' take only the first 5 digits
         timeString = timeString.Substring(0, 5)
      End If

      ' pad the empty spaces of the display String with "0"
      time = timeString.PadLeft(5, Convert.ToChar("0"))

      ' extract seconds and minutes and hours
      second = Convert.ToInt32(time.Substring(3))
      minute = Convert.ToInt32(time.Substring(1, 2))
      hour = Convert.ToInt32(time.Substring(0, 1))

      ' create Time object to contain time entered by user
      cookTime = New Time(hour, minute, second)

      ' display number of hours, minutes, and seconds
      displayButton.Text = String.Format("{0:D1}:{1:D2}:{2:D2}", _
         hour, minute, second)
   End Sub ' DisplayTime

   ' event handler displays new time each second
   Private Sub clockTimer_Tick(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles clockTimer.Tick

      ' perform countdown, subtract one second
      If cookTime.Second > 0 Then
         cookTime.Second -= 1
      ElseIf cookTime.Minute > 0 Then
         cookTime.Minute -= 1 ' subtract one minute
         cookTime.Second = 59 ' reset seconds for new minute
      ElseIf cookTime.Hour > 0 Then
         cookTime.Hour -= 1 ' subtract one hour
         cookTime.Minute = 59 ' reset minutes for new hour
         cookTime.Second = 59 ' reset seconds for new minute
      Else ' no more seconds
         clockTimer.Enabled = False ' stop the timer
         Beep() ' sound beep
         displayButton.Text = "Done!" ' display "Done" message
         windowLabel.BackColor = Label.DefaultBackColor
         Return
      End If

      ' refresh the display time
      displayButton.Text = String.Format("{0:D1}:{1:D2}:{2:D2}", _
         cookTime.Hour, cookTime.Minute, cookTime.Second)
   End Sub ' clockTimer_Tick
End Class ' MicrowaveOven