Visual Basic.NET How to Program (PDF)

372 Object-Oriented Programming: Inheritance Chapter 9
14 ' get CCircle4's initial x-y coordinates and radius
15 output = "X coordinate is " & circle.X & vbCrLf & _
16 "Y coordinate is " & circle.Y & vbCrLf & "Radius is " & _
17 circle.Radius
18
19 ' set CCircle4's x-y coordinates and radius to new values
20 circle.X = 2
21 circle.Y = 2
22 circle.Radius = 4.25
23
24 ' display CCircle4's String representation
25 output &= vbCrLf & vbCrLf & _
26 "The new location and radius of circle are " & _
27 vbCrLf & circle.ToString() & vbCrLf
28
29 ' display CCircle4's diameter
30 output &= "Diameter is " & _
31 String.Format("{0:F}", circle.Diameter()) & vbCrLf
32
33 ' display CCircle4's circumference
34 output &= "Circumference is " & _
35 String.Format("{0:F}", circle.Circumference()) & vbCrLf
36
37 ' display CCircle4's area
38 output &= "Area is " & String.Format("{0:F}", circle.Area())
39
40 MessageBox.Show(output, "Demonstrating Class CCircle4")
41 End Sub ' Main
42
43 End Module ' modCircleTest4
Fig. 9.13 modCircleTest4 demonstrates class CCircle4 functionality
(part 2 of 2).
9.5 Case Study: Three-Level Inheritance Hierarchy
Let us consider a substantial inheritance example, in which we study a point-circle-cylinder
hierarchy. In Section 9.4, we developed classes CPoint (Fig. 9.4) and CCircle4
(Fig. 9.12). Now, we present an example in which we derive class CCylinder from class
CCircle4.