[VB 2008] Potrebna pomoc za razumjevanje koda

[sankec]

Posto nisam neki expert za VB dosao sam ovamo da trazim pomoc od vas, nadam se da ce te me razumjeti.
Potrebno mi je objasnjenje koda za kalkulator u Visual basicu 2008 za skolski zadatak.Znaci sve kako sta radi po mogucnosti.

Kod koji se odnosi na broj:

If bHasFirstNumber Then
If dNumber <> 0 Then
If Me.TextBox1.Text = 0 Then
Me.TextBox1.Text = 1
bHasSecondNumber = True

Exit Sub
End If

Me.TextBox1.Text &= 1
Exit Sub
End If
Me.TextBox1.Text &= 1
Else
Me.TextBox1.Text = 1
bHasFirstNumber = True
bHasOperation = False
End If
End Sub

Kod koji se odnosi na opciju C:

Me.TextBox1.Text = 0
dNumber = 0
bHasFirstNumber = False
bHasSecondNumber = False
bHasOperation = False
sOperation = ""
End Sub

Kod koji se odnosi na +:

If bHasSecondNumber Then
If bHasOperation Then
If (sOperation = "+") Then
dNumber = Val(Me.TextBox1.Text) + dNumber
ElseIf (sOperation = "-") Then
dNumber = dNumber - Val(Me.TextBox1.Text)
ElseIf (sOperation = "*") Then
dNumber = Val(Me.TextBox1.Text) * dNumber
ElseIf (sOperation = "/") Then
dNumber = dNumber / Val(Me.TextBox1.Text)
Else
Exit Sub
End If
sOperation = "+"
bHasSecondNumber = False
Me.TextBox1.Text = 0
Exit Sub
Else
sOperation = "+"
dNumber = dNumber + Val(Me.TextBox1.Text)
bHasSecondNumber = False
Me.TextBox1.Text = 0
Exit Sub
End If
End If
If bHasFirstNumber Or bHasOperation Then
If bHasOperation Then
bHasFirstNumber = True
End If
sOperation = "+"
dNumber = Val(Me.TextBox1.Text)
Me.TextBox1.Text = 0
End If
End Sub