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Bug #48455 sprintf error when multiplying float and displaying digit
Submitted: 2009-06-02 17:51 UTC Modified: 2009-06-02 18:04 UTC
From: aldo at totalaldo dot com Assigned:
Status: Not a bug Package: Strings related
PHP Version: 5.2.9 OS: FreeBSD 7.2-RELEASE
Private report: No CVE-ID: None
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 [2009-06-02 17:51 UTC] aldo at totalaldo dot com 
Description:
------------
php -r 'echo sprintf("%6d", 34.98*100);'

output:  3497

Reproduce code:
---------------
php -r 'echo sprintf("%6d", 34.98*100);'


Expected result:
----------------
  3498

Actual result:
--------------
  3497

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 [2009-06-02 17:52 UTC] rasmus@php.net 
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://docs.sun.com/source/806-3568/ncg_goldberg.html
 
Thank you for your interest in PHP.
 [2009-06-02 18:04 UTC] aldo at totalaldo dot com 
Thank you for your prompt reply. I was aware of the limitations of 
Floating point representations.. Hopefully, anyone using similar code 
will now use another technique. 

php -r 'echo sprintf("%6s", 34.98*100);'  outputs the expected result of 
3498.
 
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