FAQ: Why is int() broken?

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

This message is one of several periodic postings to comp.lang.perl.misc
intended to make it easier for perl programmers to find answers to
common questions. The core of this message represents an excerpt
from the documentation provided with Perl.


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 above item "Why am I getting long decimals (eg,
    19.9499999999999) instead of the numbers I should be getting (eg,

    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


Documents such as this have been called "Answers to Frequently
Asked Questions" or FAQ for short.  They represent an important
part of the Usenet tradition.  They serve to reduce the volume of
redundant traffic on a news group by providing quality answers to
questions that keep coming up.

If you are some how irritated by seeing these postings you are free
to ignore them or add the sender to your killfile.  If you find
errors or other problems with these postings please send corrections
or comments to the posting email address or to the maintainers as
directed in the perlfaq manual page.

Note that the FAQ text posted by this server may have been modified
from that distributed in the stable Perl release.  It may have been
edited to reflect the additions, changes and corrections provided
by respondents, reviewers, and critics to previous postings of
these FAQ. Complete text of these FAQ are available on request.

Site Timeline