Visual Basic Procedures: Overloading a Procedure

	Overloading a Procedure

Introduction

A program involves a great deal of names that represent variables and procedures of various kinds. The compiler does not allow two variables to have the same name in the same procedure (or in the same scope). Although two procedures should have unique names in the same program, you are allowed to use the same name for different procedures of the same program following certain rules.

Overloading a Procedure

The ability to have various procedures with the same name in the same program is referred to as overloading. The most important rule about procedure overloading is to make sure that each one of these procedures has a different number or different type(s) of arguments.

Practical Learning: Overloading a Procedure

The moment of inertia is the ability of a beam to resist bending. It is calculated with regard to the cross section of the beam. Because it depends on the type of section of the beam, its calculation also depends on the type of section of the beam. In this exercise, we will review different formulas used to calculate the moment of inertia. Since this exercise is for demonstration purposes, you do not need to be a Science Engineering major to understand it.

The Moment Of Inertia

Start Microsoft Visual Basic and create a Console Application named MomentOfInertia1
In the Solution Explorer, right-click Module1.vb and click Rename
Type MomentOfInertia.vb and press Enter

To calculate the moment of inertia of a rectangle, change the file as follows:

Module MomentOfInertia

    ' Moment of Inertia
    ' Rectangle
    Private Function MomentOfInertia(ByVal b As Double, _
                                     ByVal h As Double) As Double
        Return b * h * h * h / 3
    End Function

    Public Sub Main()
        Dim Base As Double, Height As Double

        Base = InputBox("Enter the base of the Rectangle")
        Height = InputBox("Enter the height of the Rectangle")

        MsgBox("Moment of inertia with regard to the X axis" & vbCrLf & _
               "I = " & CStr(MomentOfInertia(Base, Height)) & "mm")
    End Sub

End Module

Execute the application
Enter the base as 3.25
Enter the height as 2.85
Close the DOS window and return to your programming environment

Here are the formulas to calculate the moment of inertia for a semi-circle:

The Moment of Inertia for a Circle

A circle, and thus a semi-circle, requires only a radius. Since the other version of the MomentOfInertia() function requires two arguments, we can overload it by providing only one argument, the radius.

To calculate the moment of inertia of a rectangle, change the file as follows:

Module MomentOfInertia

    ' Moment of Inertia
    ' Rectangle
    Private Function MomentOfInertia(ByVal b As Double, _
                                     ByVal h As Double) As Double
        Return b * h * h * h / 3
    End Function

    ' Semi-Circle
    Function MomentOfInertia(ByVal R As Double) As Double
        Const PI As Double = 3.14159

        Return R * R * R * R * PI / 8
    End Function

    Public Sub Main()
        ' Dim Base As Double, Height As Double
        Dim Radius As Double

        ' Base = InputBox("Enter the base of the Rectangle:")
        ' Height = InputBox("Enter the height of the Rectangle")
        ' MsgBox("Moment of inertia with regard to the X axis" & vbCrLf & _
        '       "I = " & CStr(MomentOfInertia(Base, Height)) & "mm")

        Radius = InputBox("Enter the radius of the semi-circle:")

        MsgBox("Moment of inertia of a semi-circle with " & _
	       "regard to the X axis:" & vbCrLf & _
               "I = " & CStr(MomentOfInertia(Radius)) & "mm")
    End Sub

End Module

Execute the application
Enter the radius as 6.35
Close the DOS window and return to your programming environment