Calculating a textbox's text?

[N1c0_ds]

Let's say I write "3/5*265^2" in a textbox, would there be a way to calculate the result? I can't figure out a way to do this in a simple way.

 

[klaus]

You should have a look at this program.
http://www.b4x.com/forum/code-samples-tips/1207-scientific-math-text-input-evaluator.html

Best regards.

 

[Erel]

You can use this code:

Sub Globals
    'Declare the global variables here.
    Dim numPri(30), numVal(30),numOwned(30)
    Dim Opr(30),priority(60),words(30)
    Dim numI, oprI
    pMAX = 0
End Sub

Sub App_Start
    Msgbox(Eval("2+4-5"))
    Msgbox(Eval(TextBox1.Text))
End Sub

Sub Eval(fmla)
    fmla = StrToLower(fmla)
    fmla = "0+" & fmla & "+0"
    fmla = StrReplace(fmla,"-(","-1*(")
    fmla = StrReplace(fmla," ","")
    fmlaLen = StrLength(fmla)
    c = 0
    i2 = 0
    For i = 0 To fmlaLen
        priority(i) = 0
    Next
    I = StrIndexOf(fmla,"(",0)
    If I>-1 Then
        p = 4
        fmla=StrRemove(fmla,I,1)
        priority(I)=p
        index = i
        Do While Index <= StrLength(fmla) - 1
            If StrAt(fmla,Index) = "(" Then
                p  = p + 4
                fmla = StrRemove(fmla,Index,1)
                index = index - 1
            Else If StrAt(fmla,Index) = ")" Then
                p = p - 4
                fmla = StrRemove(fmla,Index,1)
                index = index - 1
            End If
            priority(Index)=p
            index = index + 1
        Loop
    End If
    For i = 0 To StrLength(fmla) - 1
        If StrIndexOf("+-*/^",StrAt(fmla,i),0) >= 0 Then
            words(c) = SubString(fmla,i2,i-i2)
            c = c + 1
            i2 = i + 1
        End If
    Next
    words(c) = 0
    For i = 0 To c+1
        NumPri(i) = 0
        NumVal(i) = 0
        NumOwned(i) = 0
    Next
    I=-1
    oprI=0
    numI=0
    For Index = 0 To c-2
        nn=words(index)
        If StrLength(nn) = 0 Then
            words(Index+1)=StrAt(fmla,I+1) & words(Index+1)
        Else
            numI = numI +1
            i = i + StrLength(nn) + 1
            numVal(numI) = nn 
            Opr(numI) = CvrtOprToInt(StrAt(fmla,I))
            numPri(numI) = priority(I-1) + calcPRI(Opr(numI))
            If numPri(numI)>pMAX Then pMAX = numPri(numI)
        End If
    Next
    oprI=numI
    numI = numI + 1
    numVal(numI) = words(Index)
    numPri(numI) = priority(I-1)
    Return calcformula
End Sub

Sub calcFormula
    For p = pMAX To 0 Step -1
        For I = 1 To numI - 1
            If numPri(I) = p Then 
                calcBinOpr(I, Opr(I), I + 1)
                numOwned(I + 1) = I
                ans = numVal(1)
            End If
        Next
    Next
    pMAX=0
    Return ans
End Sub

Sub calcBinOpr(a,opr1,b) 
    Do While numOwned(a) > 0 
        a = NumOwned(a)
    Loop
    Do While numOwned(b) > 0 
        b = numOwned(b)
    Loop
    Select opr1
        Case 1
            NumVal(a) = NumVal(a) +  NumVal(b)
        Case 2
            NumVal(a) = NumVal(a) - NumVal(b)
        Case 3
            NumVal(a) = NumVal(a) * NumVal(b)
        Case 4
            NumVal(a) = NumVal(a) / NumVal(b)
        Case 5
            NumVal(a) = NumVal(a) ^ NumVal(b)
    End Select
End Sub
            
Sub CvrtOprToInt (oprS) 
    Select oprS
        Case "+"
            Return 1
        Case "-"
            Return 2
        Case "*"
            Return 3
        Case "/"
            Return 4
        Case "^"
            Return 5
    End Select
End Sub

Sub calcPRI(I) 
    Select I
        Case 1,2
            Return 0
        Case 3,4
            Return 1
        Case 5
            Return 2
    End Select
End Sub