I am still trying to understand pack and unpack at this time.

Here is a code sample 

#!/usr/bin/perl -w
use strict;

my ($testp, $n, $s);

$testp = 0x007102;
$n = length($testp);
$s = 2*$n;
print ("Hex 0x",unpack("H$s", $testp), "\n");

$testp = "\x30\x05\x15";
$n = length($testp);
$s = 2*$n;
print ("Hex 0x",unpack("H$s", $testp), "\n");

[download]
The results are: 
Hex 0x3238393330
Hex 0x300515

[download]
Expected results: 
Hex 0x007102
Hex 0x300515

[download]
I am trying to understand why the differences in the processes above.

Another question about dealing with Hex values in perl, what is best way to do addition and multiplication, basic math? Convert to decimal and then to the math?

Thanks Mike

In reply to Differences in behavior in pack by sxmwb

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.