package Stoplight;


sub new
{

  my ($class) = @_;

  my ($self) = {};

  bless($self,$class);

  $self->{'color'} = "yellow";

  my $var = $self->{'color'};
  print("color: $var \n");

  $self->{'_created'} = 1;

  return $self;

}

sub change
{

  my ($self) = @_;

  my $val = $self->{'color'};

  print(" color: $val \n");

  if($val eq "red")
  {
    $self->{'color'} = "green";
  }
  elsif($val eq "green")
  {
    $self->{'color'} = "yellow";
  }
  elsif($val eq "yellow")
  {
    $self->{'color'} = "red";
  }

}


1;