KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q164359: BUG: Incorrect Evaluation of Equation with Variables

Article: Q164359
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,6.0
Operating System(s): 
Keyword(s): kbvfp kbvfp500bug kbvfp600bug
Last Modified: 05-FEB-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 5.0, 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

In Visual FoxPro 5.0 and higher, an equation that contains variables may not be
evaluated correctly.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

In the Command window, issue the following commands:

     SET DECIMALS TO 5
     mVar = 1
     ? mVar + (1048575+(mVar/1000)) = 1048576.001

The value .T. (True) should be echoed to the screen but .F. is returned instead.

The following recommendations may be used as alternative solutions to this
problem:

- Replacing mVar (inside the parentheses) with 1 exhibits the correct behavior,
  as does removing the outside parentheses.

- Using the ROUND() function may also solve this problem:

        ? ROUND(mVar+(1048575+(mVar/1000)), 5) = 1048576.001

This behavior does not occur in Visual FoxPro 3.0.

Additional query words:

======================================================================
Keywords          : kbvfp kbvfp500bug kbvfp600bug 
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600
Version           : WINDOWS:5.0,6.0

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.