"my" variable $k masks earlier declaration in same scope at a.pl line 6.

##</code><code>##

use strict;

my $k = 1;
print "wanted: \$k = $k, got " . InvestigateValue() . "\n";

$k = 2;#modified
print "wanted: \$k = $k, got " . InvestigateValue() . "\n";

sub InvestigateValue
{
    return defined $k ? $k : 'undef';
}