Both 1/10 and 16/10 are periodic numbers in binary, just like 1/3 is in decimal. It would take an infinite amount of memory to store 0.1 and 1.6 as floats. Some rounding error occurs. 

$ perl -e' printf "%.20f\n", 1.6;'
1.60000000000000008882

[download]
And to see what's happening for you: 
$ perl -e'
   for ($i=1.1;$i<=1.6;$i+=.1) { printf "%.20f\n", $i; }
   printf "\n%.20f\n", $i;
'
1.10000000000000008882
1.20000000000000017764
1.30000000000000026645
1.40000000000000035527
1.50000000000000044409

1.60000000000000053291

[download]

One solution is to use integers for the counter, and generate the floats from them 

$ perl -le'for my $i (1..6) { print 1+$i/10 }'
1.1
1.2
1.3
1.4
1.5
1.6

[download]

It gives precise checks for the loop, and there's no accumulation of error for the result.

In reply to Re: Floating Point Looping In Perl by ikegami
in thread Floating Point Looping In Perl by kiruthika.bkite

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.