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Posted by PerlFAQ Server on May 6, 2008, 9:03 am
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This is an excerpt from the latest version perlfaq4.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .
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4.2: Why is int() broken?
Your "int()" is most probably working just fine. It's the numbers that
aren't quite what you think.
First, see the answer to "Why am I getting long decimals (eg,
19.9499999999999) instead of the numbers I should be getting (eg,
19.95)?".
For example, this
print int(0.6/0.2-2), "\n";
will in most computers print 0, not 1, because even such simple numbers
as 0.6 and 0.2 cannot be presented exactly by floating-point numbers.
What you think in the above as 'three' is really more like
2.9999999999999995559.
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