Ohm's Law Calculator 1.0

hi everyone!
I need some help with my rpn calculator.
I first translated it from vbscript to autoitscript and that's when i stumbled on problem one:
(46) : ==> Array variable has incorrect number of subscripts or subscript dimension range exceeded.:
$Stack[ubound($Stack)] = $Item
^ ERROR
After that (and i know this from testing it as a vbscript) it can't work with negative numbers:
"1 - - 2" to Reverse Polish notation = "1 - 2 -" gives me the build in error...
 
Can you guy's help me with my code pleas?
Func Print($what,$er = 0) $t = '' if $err <> 0 then $t = 'ERROR!' MsgBox($er,$st,$what) EndFunc Func RPN($Tokenarray) Local $Stack = [] Local $Result Local $Operator_B Local $Operator_A For $Token = 0 To Ubound($Tokenarray) If Isoperator($Tokenarray[$Token]) Then $Operator_B = Pop($Stack) $Operator_A = Pop($Stack) If $Operator_A = "" Then Print("The user has not input sufficient values in the expression.",16) exit EndIf Switch $Tokenarray[$Token] Case "+" $Result = Number($Operator_A,3) + Number($Operator_B,3) Case "-" $Result = Number($Operator_A,3) - Number($Operator_B,3) Case "*" $Result = Number($Operator_A,3) * Number($Operator_B,3) Case "/" $Result = Number($Operator_A,3) / Number($Operator_B,3) Case "^" $Result = Number($Operator_A,3) ^ Number($Operator_B,3) EndSwitch Push($Result,$Stack) Else Push($Tokenarray[$Token],$Stack) EndIf Next If Ubound($Stack) > 1 Then Print("The user input has too many values.",16) Exit EndIf Return pop($Stack) EndFunc Func Push($Item, Byref $Stack) If Ubound($Stack) > -1 Then Redim $Stack[Ubound($Stack) + 1] $Stack[Ubound($Stack)] = $Item Else Local $Stack = [$Item] EndIf EndFunc Func Pop($Stack) $pop = "" If Ubound($Stack) > -1 Then $Pop = $Stack[Ubound($Stack)] Redim $Stack[Ubound($Stack) - 1] EndIf Return $pop EndFunc Func Peek($Stack) $peek = "" If Ubound($Stack) > -1 Then $Peek = $Stack(Ubound($Stack)) EndIf Return $peek EndFunc Func Isoperator($Operator) Return StringInstr("+-*/^&<=>", $Operator) <> 0 And StringLen($Operator) = 1 EndFunc Func Precedence($Operator) If Isoperator($Operator) Then Switch $Operator case "^" Return 4 case "*","/" Return 3 case "+","-" Return 2 case "&" Return 1 case "<","=",">" Return 0 EndSwitch EndIf EndFunc ;################################################################################################## ; (4 - -5) = (4|-|-|5) = (4|-|5|-) ; input tokens rpn Global $calculate_this = ["4","-","5","-"] Print(rpn($calculate_this)) thanks in advance ,
TheAutomator

Reverse Polish Notation (RPN) is a math notation in which each operator follows its two operands. I own an HP 48G calculator which uses RPN, and when I tried to use the windows calculator I had so much trouble that I wrote my own calculator. Basically, it has a stack of numbers; any time an operator is pressed, that operation is carried out immediately on the two items on the bottom of the stack, or the stack and the input if there is anything in the input. This method reduces the requirements for parenthesis and makes calculating equations/functions relatively easy: instead of
(sqrt(5+8))/(8*9)
you would enter
5 ENTER 8 + SQRT 8 ENTER 9 * /

Practical implications

Suggestions/advice/criticisms are greatly appreciated!
calc2.au3

Here's a graphing calculator I've been making,
It can graph most functions and solve basic derivatives and integrals

I haven't gotten around to making functions for solving indefinite integrals yet,
and i know that my derivative functions don't work for all types of functions.

please post any feedback,

BuckMaster
Graphing Calc.rar