KnowledgeBase Archive

An Archive of Early Microsoft KnowledgeBase Articles

View on GitHub

Q192303: HOWTO: Convert Decimal Integers to Hexadecimal Strings

Article: Q192303
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,5.0a,6.0
Operating System(s): 
Keyword(s): 
Last Modified: 14-AUG-1999

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

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

SUMMARY
=======

The following Microsoft Knowledge Base article describes how to convert decimal
integers to a hexadecimal string:

  Q95717 How to Convert Decimal Numbers to Hexadecimal Numbers

However, the function in the article is limited in the size of the integer it can
convert. In Visual FoxPro, the TRANSFORM() function can be used to convert
decimal integers to hexadecimal strings. However, TRANSFORM() cannot handle
negative decimal integers (for example, TRANSFORM(-2, "@0")).

This article demonstrates how to use the DecToHex function to convert any decimal
integer (up to DWORD in size) to a hexadecimal string, regardless of the sign of
the integer.

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

The following code demonstrates how to use the DecToHex() function to convert
decimal integers to a string containing the equivalent hexadecimal number.

Sample Code
-----------

     *-- Code begins here.
     WAIT WINDOW "-" + STR(2146828218) + " = " + DecToHex(-2146828218)
     WAIT WINDOW STR(-43690) + " = " + DecToHex(-43690)
     WAIT WINDOW STR(43690) + " = " + DecToHex(43690)

     *-----------------------------------------------------------------
     *- Function:    DecToHex
     *- Summary:     Converts decimal integers to hex strings, whether
     *-              signed or unsigned.
     *- Parameters:  liDecNumber - decimal number to convert.
     *-----------------------------------------------------------------
     FUNCTION DecToHex
     PARAMETERS liDecNumber
     lsHexNumber = ""
     IF liDecNumber > 0 && It's not negative, so do a straight TRANSFORM.
        lsHexNumber = TRANSFORM(liDecNumber, "@0")
     ELSE

        *-- The number is negative, so we'll have to do a little more work,
        *-- since it's not as straight forward as converting and adding a
        *-- minus sign.

        *-- Find the length of the resulting hex string.
        lsHexNumber = TRANSFORM(ABS(liDecNumber), "@0")
        IF SUBSTR(lsHexNumber, 3, 1) = "0" && The number has filled the
                                           && eight places of DWORD.
           liLength = LEN(SUBSTR(lsHexNumber, NotAt("0", lsHexNumber, 2)))
        ELSE
           *-- Subtract to account for "0x".
           liLength = LEN(TRANSFORM(ABS(liDecNumber), "@0")) - 2
        ENDIF

        lsTempHex = 0xFFFFFFFF
        lsHexNumber = TRANSFORM(lsTempHex-ABS(liDecNumber) + 1, "@0")
     ENDIF
     RETURN lsHexNumber

     *-----------------------------------------------------------------
     *- Function:    NotAt
     *- Summary:     From within a passed string, finds the first
     *-              occurrence of a character that is not the character
     *-              specified.  In other words, this function works
     *-              opposite of the manner that AT() does.
     *- Parameters:  lsNotString -    What we don't want.  The function
     *-                               finds the first character that is
     *-                               not lsNotString.
     *-              lsSearchString - The string in which to search.
     *-              liOccurence -    Indicates that NotAt should find
     *-                               the liOccurence of a character
     *-                               that is not lsNotString.
     *-----------------------------------------------------------------
     FUNCTION NotAt()
     PARAMETERS lsNotString, lsSearchString, liOccurrence

     llFound       = .F.  && Flag indicates if we've found a character that
                          && is NOT lsNotString
     llEndOfString = .F.  && Flag to indicate that we've reached the end
                          && of the string.
     lnCounter     = 0    && Tracks position during the search.
     lnLength      = LEN(lsSearchString)
     liOccurCount  = 0    && Tracks how many occurrences have been found.

     *-- Loop until the desired character is found or the end of
     *-- the string is reached.
     DO WHILE NOT llFound AND NOT llEndofString
        lnCounter = lnCounter + 1
        lsCompare = SUBSTR(lsSearchString, lnCounter, 1)
        IF lsCompare <> lsNotString
           liOccurCount = liOccurCount + 1

           *-- Have we found the occurrence we want?
           IF liOccurCount = liOccurrence
              llFound = .T.
           ENDIF
        ENDIF
        IF lnCounter = lnLength
           llEndOfString = .T.
        ENDIF

     ENDDO
     RETURN lnCounter
     *-- Code ends here.

REFERENCES
==========

For additional information, please see the following articles in the Microsoft
Knowledge Base:

  Q95717 How to Convert Decimal Numbers to Hexadecimal Numbers

  Q155389 How To Convert Values to Hexadecimal Format with Xbase

(c) Microsoft Corporation 1998. All Rights Reserved. Contributions by Mike A.
Stewart, Microsoft Corporation.


Additional query words: kbVFp500a kbVFp500 kbVFp600 kbXBase

======================================================================
Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:5.0,5.0a,6.0
Issue type        : kbhowto

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

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.

Copyright Microsoft Corporation 1986-2002.