Attribute VB_Name = "Ch3"
Type Point
  x As Double
  y As Double
End Type


Sub ch3_4_ex()
  Dim L1 As New Line1
  L1.refPointX = 1
  L1.refPointY = 2
  L1.slope = 1
  MsgBox "c = " & L1.getYIntercept
  MsgBox "Equation: " & L1.getEquation
End Sub

Sub ch3_5_ex()
  Dim p1 As Point
  With p1
    .x = 1
    .y = 2
  End With
  Dim L1 As New Line2
  L1.mRefPointX = p1
  
  L1.slope = 3
  
  MsgBox L1.slope
End Sub

Sub ch3_5_ex2()
  Dim p1 As Point
  With p1
    .x = 1
    .y = 2
  End With
  Dim L1 As New Line3
  L1.refPoint = p1
  L1.slope = 1
  MsgBox "c = " & L1.getYIntercept
  MsgBox "Equation: " & L1.getEquation
End Sub

Sub ch3_10_ex1()
  Dim aLine As Line, aQuadraticCurve As QuadraticCurve
  Dim aPoint As Point
  Dim aCurve(3) As Curve
  
  'data entry
  Set aLine = New Line
  aPoint.x = 1
  aPoint.y = 2
  aLine.initialize aPoint, 1
  Set aCurve(0) = aLine
  
  Set aLine = New Line
  aPoint.x = 2
  aPoint.y = 3
  aLine.initialize aPoint, 4
  Set aCurve(1) = aLine
  
  Set aQuadraticCurve = New QuadraticCurve
  aQuadraticCurve.initialize 1, 2, 1
  Set aCurve(2) = aQuadraticCurve
  
  Set aQuadraticCurve = New QuadraticCurve
  aQuadraticCurve.initialize 2, 5, 2
  Set aCurve(3) = aQuadraticCurve
  
  Dim i As Integer, str As String
  For i = 0 To 3
    str = "Equation of Curve " & i + 1 & ": " & aCurve(i).getEquation 'notice Polymorphism
    str = str & vbCrLf & "Y-intercept: " & aCurve(i).getYIntercept
    
    If TypeOf aCurve(i) Is QuadraticCurve Then 'notice the use of TypeOf...Is to check type
      Set aQuadraticCurve = aCurve(i)
      str = str & vbCrLf & "Extreme point: (" & aQuadraticCurve.getExtremePoint.x & _
        ", " & aQuadraticCurve.getExtremePoint.y & ")"
    End If
    
    MsgBox str
  Next i
End Sub

Sub ch3_10_ex2()
  Randomize
  
  'initialize two stocks
  Dim s1 As New ContDivStock
  Dim s2 As New DiscDivStock
  s1.initialize "Stock 1", 100, 0.4, 0.03, 0.02, 0.03
  s2.initialize "Stock 2", 100, 0.4, 0.03, 0.02, 2
  
  'select stock 1 or stock 2
  Dim choice As Integer
  choice = InputBox("Select a stock:")
  
  Dim s As Stock
  If choice = 1 Then
    Set s = s1
  ElseIf choice = 2 Then
    Set s = s2
  Else
    MsgBox "Invalid Choice!"
    Exit Sub
  End If
  
  'advance 100 days
  s.advance 100
  
  'pay dividend
  If TypeOf s Is ContDivStock Then
    Dim tempStockC As ContDivStock
    Set tempStockC = s
    tempStockC.payDividend
  ElseIf TypeOf s Is DiscDivStock Then
    Dim tempStockD As DiscDivStock
    Set tempStockD = s
    tempStockD.payDividend
  End If
  
  'show percentage gain
  MsgBox "The percentage gain for " & s.stockName & ": " & Round(s.percentGain * 100, 2) & "%"
End Sub

Sub ch3_11_ex()
  Dim aLine As Line, aQuadraticCurve As QuadraticCurve
  Dim aPoint As Point
  Dim aCurve As New Collection
  
  'data entry
  Set aLine = New Line
  aPoint.x = 1
  aPoint.y = 2
  aLine.initialize aPoint, 1
  aCurve.Add aLine
  
  Set aLine = New Line
  aPoint.x = 2
  aPoint.y = 3
  aLine.initialize aPoint, 4
  aCurve.Add aLine
  
  Set aQuadraticCurve = New QuadraticCurve
  aQuadraticCurve.initialize 1, 2, 1
  aCurve.Add aQuadraticCurve
  
  Set aQuadraticCurve = New QuadraticCurve
  aQuadraticCurve.initialize 2, 5, 2
  aCurve.Add aQuadraticCurve
  
  Dim i As Integer, str As String
  For i = 1 To 4
    str = "Equation of Curve " & i & ": " & aCurve(i).getEquation 'notice Polymorphism
    str = str & vbCrLf & "Y-intercept: " & aCurve(i).getYIntercept
    
    If TypeOf aCurve(i) Is QuadraticCurve Then 'notice the use of TypeOf...Is to check type
      Set aQuadraticCurve = aCurve(i)
      str = str & vbCrLf & "Extreme point: (" & aQuadraticCurve.getExtremePoint.x & _
        ", " & aQuadraticCurve.getExtremePoint.y & ")"
    End If
    
    MsgBox str
  Next i
End Sub