Purpose

This is the eMbedded Visual Basic version of our combination application.

 Requirements

 Source code

Below is the .ebf file, which contains our main (and only) form along with its event handlers and the application's logic.

For .ebp (the project file), .vbw (the workspace) and .vb (the executable) please download the ZIP file.

Rem Combination.ebf
Rem Pocket PC
Rem Visual Basic


Option Explicit


Private Function Factorial(n)
    If n > 1 Then
        Factorial = n * Factorial(n - 1)
        Else: Factorial = 1
    End If
End Function

Private Function Combination(n, p)
    Combination = Factorial(n) / (Factorial(n - p) * Factorial(p))
End Function

Private Sub Compute()
    Dim intN, intP As Integer
    
    Rem Let's make sure the user input positive integers
    
    On Error Resume Next
    intN = n
    
    On Error Resume Next
    intP = p
    
    If (intN <= 0) Or (intP <= 0) Then
        MsgBox "Please do NOT input crap! Values HAVE to be positive integers..."
        Exit Sub
    End If
    
    Rem Now, we do the job
    factorialN.Text = Factorial(n)
    factorialP.Text = Factorial(p)
    factorialNP.Text = Factorial(n - p)
    combinationNP.Text = Combination(n, p)
End Sub

Private Sub Compute_Click()
    Rem User clicked on 'Compute' button, so we DO compute
    Compute
End Sub

Private Sub Form_OKClick()
    Rem User clicked OK to close the application - Time to say good bye
    App.End
End Sub

 Comments

See for yourself how compact this source code is. The embedded version of Visual Basic benefits from the model and features of the desktop version of VB. It is thus UI-oriented in its way of guiding you to develop an app.

The core functions are located in Factorial(), Combination() and Compute(). You'll notice that in most of our other samples, we used Go instead of Compute. We had to use Compute here because Go is a reserved keyword in VB.

Note that there's hardly any overhead for system or UI stuff.

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