use strict;
use warnings;

my $query = new MyPackage::Query("utf8"); 
my $query2 = new MyPackage::Query("euc-jp");

print "QUERY: [$query->{input_enc}]\n";
print "QUERY2: [$query2->{input_enc}]\n";

print "Done\n";

package MyPackage::Query;

sub new {
    my $class = shift;

    my $self  = {};
    bless($self, $class);

    $self->{input_enc} = shift;  
    
    unless (defined $self->{input_enc}) {
    $self->{input_enc} = "euc-jp";
    }

    #...

    return $self;
}

##</code><code>##

F:\>perl test_object_creation.pl
QUERY: [utf8]
QUERY2: [euc-jp]
Done