In this node, a question was asked on how to get leading 0's on a numerical input from a cgi script. dmmiller2k offers some good info on the subject of not using numerical methods on strings to keep them strings. And this is where my question lies. How/why does perl keep the leading 0 in some cases, but not in others? The below example and output demonstrate: 
use warnings;
use strict;

my $v = 99;

$v = sprintf( "%04d", $v );
print "$v\n";
++$v;
print "$v\n";

[download]
The output is:
0099
0100
200

[download]
Adding 1 to 99 and getting 100 shows that we're not incrementing in string land, so why does one numerical method preserve the leading 0 and not the other?
Thank you for your enlightnment.

In reply to Leading zero's, and their persistance by LogicalChaos

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