package Round;

sub new
{
    my $class = shift;
    my %args  = @_;

    my $self = {};
    $self->{_$_} = $args{$_} for qw(
        roundnum room judge type code contestants
    );
    bless $self, $class;
}

sub roundnum
{
    my $self = shift;

    $self->{_roundnum} = shift if @_;
    $self->{_roundnum};
}
-------------

use Round;
my $test = Round->new( roundnum => 1 );
my $testval = $test->roundnum;
print "$testval\n";