The Code

​

 

 

 

 

Public Class Form1

​

    '## Functions can be called by (Value) or called by (Reference)
    '## By default, the Arguments are passed by (Reference).
    '## Original Data will be modified and (No Longer Preserved).
    '## On one Hand, if Arguments are passed by (Value), original
    '## Data will be preserved. The keyword to pass Arguments
    '## By (Reference) is (ByRef) and the keyword to pass Arguments 
    '## by (Value) is (ByVal).

    '## Example :
    '## Private Function FV(ByVal PV AS Single, ByRef i as Single, n as Integer) as Double

​

    Private Function sqroot(ByRef x As Single) As Double
        'Exponent x = x ^ 0.5 - (Square Root Value of x)
        x = x ^ 0.5
        sqroot = x
    End Function

​

    Private Function sqroot1(ByVal y As Single) As Double
        '## Exponent y = y ^ 0.5 (Square Root Value of y)
        y = y ^ 0.5
        sqroot1 = y
    End Function

​

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

        Dim u As Single
        u = 9
        MsgBox(3 * sqroot(u), , "ByRef")  
        MsgBox("Value of u is " & u, , "ByRef")

    End Sub

​

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

        Dim u As Single
        u = 9
        MsgBox(3 * sqroot1(u), , "ByVal")
        MsgBox("Value of u is " & u, , "ByVal")

    End Sub

End Class

 

​

​