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error handling for calculator

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davext

davext

Programmer
Oct 6, 2003
18
CA
Here is a calculator I'm trying to work with, does anyone know how to error trap so that if someone types in a non-numeric value, the display will read "NaN".. for the program below, an error just pops up. I'm new to VBScript. Any help is much appreciated!


<!DOCTYPE HTML PUBLIC &quot;-//W3C//DTD HTML 4.0 Transitional//EN&quot;>


<!-- Recommended template for
Microsoft Visual Basic Scripting-Enabled Pages -->
<HTML>
<HEAD><TITLE>VBScript sample: Calculator</TITLE></HEAD>

<body background=&quot;brick3.gif&quot;><center>

<center>

<!--
Microsoft VBScript sample
VBScript: The easiest, most powerful way to program custom web solutions.
-->

<FONT FACE=ARIAL SIZE=3> <!-- global default -->

<SCRIPT LANGUAGE=&quot;VBScript&quot;>
<!--
' Module-level variables
Dim Accum ' Previous number (operand) awaiting operation
Dim FlagNewNum ' Flag to indicate a new number (operand) is being entered
Dim PendingOp ' Pending operation waiting for completion of second operand

Sub NumPressed(Byval Num)

If FlagNewNum Then
Document.Keypad.Readout.Value = Num
FlagNewNum = False
Else
If Document.Keypad.Readout.Value = &quot;0&quot; Then
Document.Keypad.Readout.Value = CStr(Num)
Else
Document.Keypad.ReadOut.Value= Document.Keypad.ReadOut.Value & CStr(Num)
End If
End If

End Sub

Sub Decimal_onClick()
Dim curReadout
curReadOut = Document.Keypad.ReadOut.Value
If FlagNewNum Then
curReadOut = &quot;0.&quot;
FlagNewNum = False
Else
If InStr(curReadOut, &quot;.&quot;) = 0 Then
curReadOut = curReadOut & &quot;.&quot;
End If
End If
Document.Keypad.ReadOut.Value = curReadOut
End Sub

Sub Plus_onClick()
Operation &quot;+&quot;
End Sub

Sub Minus_onClick()
Operation &quot;-&quot;
End Sub

Sub Multiply_onClick()
Operation &quot;*&quot;
End Sub

Sub Divide_OnClick()
Operation &quot;/&quot;
End Sub

Sub Operation(Byval Op)
Dim Readout
Dim Zero

ReadOut = Document.Keypad.ReadOut.Value
If FlagNewNum and PendingOp <> &quot;=&quot; Then
' User is hitting op keys repeatedly, so don't do anything
Else
FlagNewNum = True
Select Case PendingOp
Case &quot;+&quot;
Accum = CDbl(Accum) + CDbl(ReadOut)
Case &quot;-&quot;
Accum = CDbl(Accum) - CDbl(ReadOut)
Case &quot;/&quot;
Zero=CDbl(ReadOut)
if Zero=0 then
Document.Keypad.ReadOut.Value=&quot;Infinity&quot;
Accum=&quot;Infinity&quot;
Else
Accum = CDbl(Accum) / CDbl(ReadOut)

End If

Case &quot;*&quot;
Accum = CDbl(Accum) * CDbl(ReadOut)
Case Else
Accum = ReadOut
End Select
Document.Keypad.ReadOut.Value = Accum
PendingOp = Op
End If
End Sub

Sub ClearEntry_onClick()
' Remove current number and reset state
Document.Keypad.ReadOut.Value = &quot;0&quot;
FlagNewNum = True
End Sub

Sub Clear_onClick()
' Clear accumulator and pending operation, and clear display
Accum = 0
PendingOp = &quot;&quot;
ClearEntry_onClick
End Sub

Sub Neg_onClick()
Document.Keypad.ReadOut.Value = CDbl(Document.Keypad.ReadOut.Value) * -1
End Sub

Sub Percent_onClick()
Document.Keypad.ReadOut.Value = (CDbl(Document.Keypad.ReadOut.Value) / 100) * Accum
End Sub

Sub Equals_OnClick()
Operation &quot;=&quot;
End Sub

-->
</SCRIPT>


<FORM Name=&quot;Keypad&quot;>
<TABLE>
<B>
<TABLE background=&quot;brick4.jpg&quot; BORDER=2 WIDTH=50 HEIGHT=60 CELLPADDING=1 CELLSPACING=5>
<CAPTION ALIGN=top>

</CAPTION>
<TR>
<TD COLSPAN=3 ALIGN=MIDDLE><INPUT NAME=&quot;ReadOut&quot; TYPE=&quot;Text&quot; SIZE=24 VALUE=&quot;0&quot; WIDTH=100%></TD>
<TD></TD>
<TD><INPUT NAME=&quot;Clear&quot; TYPE=&quot;Button&quot; VALUE=&quot; C &quot; ></TD>
<TD><INPUT NAME=&quot;ClearEntry&quot; TYPE=&quot;Button&quot; VALUE=&quot; CE &quot; ></TD>
</TR>
<TR>
<TD><INPUT NAME=&quot;Seven&quot; TYPE=&quot;Button&quot; VALUE=&quot; 7 &quot; OnClick=&quot;NumPressed(7)&quot;></TD>
<TD><INPUT NAME=&quot;Eight&quot; TYPE=&quot;Button&quot; VALUE=&quot; 8 &quot; OnClick=&quot;NumPressed(8)&quot;></TD>
<TD><INPUT NAME=&quot;Nine&quot; TYPE=&quot;Button&quot; VALUE=&quot; 9 &quot; OnClick=&quot;NumPressed(9)&quot;></TD>
<TD></TD>
<TD><INPUT NAME=&quot;Neg&quot; TYPE=&quot;Button&quot; VALUE=&quot; +/- &quot; ></TD>
<TD><INPUT NAME=&quot;Percent&quot; TYPE=&quot;Button&quot; VALUE=&quot; % &quot; ></TD>
</TR>

<TR>
<TD><INPUT NAME=&quot;Four&quot; TYPE=&quot;Button&quot; VALUE=&quot; 4 &quot; OnClick=&quot;NumPressed(4)&quot;></TD>
<TD><INPUT NAME=&quot;Five&quot; TYPE=&quot;Button&quot; VALUE=&quot; 5 &quot; OnClick=&quot;NumPressed(5)&quot;></TD>
<TD><INPUT NAME=&quot;Six&quot; TYPE=&quot;Button&quot; VALUE=&quot; 6 &quot; OnClick=&quot;NumPressed(6)&quot;></TD>
<TD></TD>
<TD ALIGN=MIDDLE><INPUT NAME=&quot;Plus&quot; TYPE=&quot;Button&quot; VALUE=&quot; + &quot; ></TD>
<TD ALIGN=MIDDLE><INPUT NAME=&quot;Minus&quot; TYPE=&quot;Button&quot; VALUE=&quot; - &quot; ></TD>
</TR>
<TR>
<TD><INPUT NAME=&quot;One&quot; TYPE=&quot;Button&quot; VALUE=&quot; 1 &quot; OnClick=&quot;NumPressed(1)&quot;></TD>
<TD><INPUT NAME=&quot;Two&quot; TYPE=&quot;Button&quot; VALUE=&quot; 2 &quot; OnClick=&quot;NumPressed(2)&quot;></TD>
<TD><INPUT NAME=&quot;Three&quot; TYPE=&quot;Button&quot; VALUE=&quot; 3 &quot; OnClick=&quot;NumPressed(3)&quot;></TD>
<TD></TD>
<TD ALIGN=MIDDLE><INPUT NAME=&quot;Multiply&quot; TYPE=&quot;Button&quot; VALUE=&quot; * &quot; ></TD>
<TD ALIGN=MIDDLE><INPUT NAME=&quot;Divide&quot; TYPE=&quot;Button&quot; VALUE=&quot; / &quot; ></TD>
</TR>
<TR>
<TD><INPUT NAME=&quot;Zero&quot; TYPE=&quot;Button&quot; VALUE=&quot; 0 &quot; OnClick=&quot;NumPressed(0)&quot;></TD>
<TD><INPUT NAME=&quot;Decimal&quot; TYPE=&quot;Button&quot; VALUE=&quot; . &quot; ></TD>
<TD COLSPAN=3></TD>
<TD><INPUT NAME=&quot;Equals&quot; TYPE=&quot;Button&quot; VALUE=&quot; = &quot;></TD>
</TR>
</TABLE>
</TABLE>
</B>
</FORM>

</font>

</BODY>
</HTML>
 
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You should first read faq222-2244, especially paragraph 3. This will lead you to post your VBScript questions in the VBScript forum. This is the VB6 forum - you're looking for forum329

Good luck there

________________________________________________________________
If you want to get the best response to a question, please check out FAQ222-2244 first

'People who live in windowed environments shouldn't cast pointers.'
 
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