[Doctor GME]

حاولت برمجة برنامج آلة حاسبة
نجحت فى تنفيذ عملية بسيطة فقط مثل 2 + 2
ولكن عند محاولة أداء عملية أعقد مثل:
2 + 2 + 2
أو مثلاُ
2 + 2 - 5 * 8
لم أنجح فى أدائها
وهذا كود البرنامج بالكامل
علماً بأن function هنا تعطى عند التنفيذ دائماً Invalid Operation

كود :

 Private Function DoMath(equation) As String
       Dim equationString As String = (equation)
       Dim lettersAloud() As Char = {"+", "-", "/", "*"}
       Dim mOperator As String = (equationString.IndexOfAny(lettersAloud))
       Dim num1 As String = (Mid(equationString, 1, mOperator - 1))
       Dim num2 As String = (Mid(equationString, mOperator + 1, equationString.Length))
       Dim answer As Double
       If (mOperator = ("+")) Then
           answer = (CInt(num1) + CInt(num2))
       ElseIf (mOperator = ("-")) Then
           answer = (CInt(num1) - CInt(num2))
       ElseIf (mOperator = ("*")) Then
           answer = (CInt(num1) * CInt(num2))
       ElseIf (mOperator = ("/")) Then
           answer = CInt(num1) / CInt(num2)
       Else
           Return ("Invalid Operation")
       End If
       Return (answer.ToString)
   End Function
   Private Sub buttons(sender As Object, e As EventArgs) Handles Btn0.Click, Btn1.Click, Btn2.Click, Btn3.Click, Btn4.Click, Btn5.Click, Btn6.Click, Btn7.Click, Btn8.Click,
       Btn9.Click

       If CalculatorText.Text = "" Then
           CalculatorText.Text = sender.text
       Else CalculatorText.Text = CalculatorText.Text & sender.text
       End If

   End Sub
   Private Sub BtnPoint_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnPoint.Click
       CalculatorText.Text += BtnPoint.Text
   End Sub
   Private Sub BtnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnClear.Click
       CalculatorText.Clear()
       CalculatorResult.Clear()
   End Sub
   Private Sub BtnPlus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnPlus.Click
       CalculatorText.Text += "+"
   End Sub
   Private Sub BtnMinus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnMinus.Click
       CalculatorText.Text += "-"
   End Sub
   Private Sub BtnDivide_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDivide.Click
       CalculatorText.Text += "/"
   End Sub
   Private Sub BtnMultiply_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnMultiply.Click
       CalculatorText.Text += "*"
   End Sub
   Private Sub BtnResult_Click(sender As Object, e As EventArgs) Handles BtnResult.Click
       CalculatorResult.Text = DoMath(CalculatorText.Text)
   End Sub