"Execute" calculations

[Jop]

I want to do this:
I want my prog to solve calculations (with unknowns (x, y))
Can I do like:
"enter formula in the textbox"
Press a button and then actually get the 'code' excecuted?
I can do
Formula = Text1.Text
but then it's just passed as a string and not 'executed' in any way!?
Thanks!

[GRAHAM]

Is this what you're looking for:

Private Sub cmd1_Click()

Dim myResult As Single 'or Double

myResult = Val(Text1.Text * Text2.Text)
Text3.Text = myResult
End Sub

GRAHAM

[BruceG]

I don't believe there is an "automatic" way to do this. You will need to parse the textbox expression to see if its valid, then if so, write the code to carry out the operations specified in the expression.

I'll try to give a simple example. Suppose a vaild expression had to be in this form:
[variable] [operator] [variable]
where the variable had to be x, y, or z and the operator had to be +, -, *, or /. It would be assumed that the values for x, y, and z were established beforehand. (Depending on what expressions you want to support, your parsing routine will be much more complex.)

Private Sub cmdExecute_Click()

    Dim arrTokens() As String
    Dim dblVar1     As Double
    Dim dblVar2     As Double
    Dim dblResult   As Double

    arrTokens = Split(Trim$(Text1.Text))

    If UBound(arrTokens) <> 2 Then GoTo BadExpression

    Select Case arrTokens(0)
        Case "x" : dblVar1 = x
        Case "y" : dblVar1 = y
        Case "z" : dblVar1 = z
        Case Else
            GoTo BadExpression
     End Select    

    Select Case arrTokens(2)
        Case "x" : dblVar2 = x
        Case "y" : dblVar2 = y
        Case "z" : dblVar2 = z
        Case Else
            GoTo BadExpression
     End Select    

    Select Case arrTokens(1)
        Case "+" : dblResult = dblVar1 + dblVar2
        Case "-" : dblResult = dblVar1 - dblVar2
        Case "* : dblResult = dblVar1 * dblVar2
        Case "/" : dblResult = dblVar1 / dblVar2
        Case Else
            GoTo BadExpression
     End Select    

     ' If we make it to this point, we had a valid expression ...  
     Text2.Text = dblResult

     Exit Sub

BadExpression: 
        MsgBox "Expression not valid", vbexclamation, "Bad Expression"
        Text1.SetFocus
End Sub