Floating point numbers are a subset of rational numbers. Just like 1/3 cannot be exactly represented by a finite decimal number (0.33333.....), as it cannot be represented by a finite expansion of powers of ten, numbers that can't be represented as a finite sum of powers of two cannot be represented as floating point numbers. There are quite a few programmers (see na-net) who have to deal with this all the time, as when trying to solve a 100000 DOF finite element model. Most perlists don't have to do such things (that sort of programming is still largely done in Fortran, although C++ is becoming more prevalent). In other words, it's expected behavior unless you're using a package like Macsyma or Maple.

See, for example, "What Every Programmer Should Know about Floating Point" by David Goldberg.

emc

Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.

Albert Einstein

In reply to Re: strange result for a simple addition ?? by swampyankee
in thread strange result for a simple addition ?? by Marsel

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.