Both valdez and demerphq have excellent (and overlapping) points. I would like to point out that the proximate issue is the use of defined() and chomp() in the while statement. chomp() never returns an undefined value. Better (though I personally write it as demerphq does) would have been: 
while (chomp(my $qline = <QINPUT>))
{
   # yadda, yadda, yadda
}

[download]

Though, this will fail to read the last line if it doesn't contain a newline at the end of it. (Similar to the "Incomplete last line" error vi gives you in the same situation.)

Just do what demerphq or valdez (through the link provided) suggest.

------
We are the carpenters and bricklayers of the Information Age.

Please remember that I'm crufty and crochety. All opinions are purely mine and all code is untested, unless otherwise specified.

In reply to Re: WHILE and DEFINED problem by dragonchild
in thread WHILE and DEFINED problem by eldinkim

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.