I have a package car. What i need is a variable that counts the number of objects derived from this class. Say i have a car rental company and want to keep track of the number of cars being rented, each time a car object is being created means 1 car has been rented. I have been looking on the internet but can't find anything. How can i do this(if possible at all)? Here is the car.pm file:

use strict;
use warnings;

package car;

sub new {
    my $class = shift;
    my $self = {
        name => shift,
        price => shift,
        speed => 0
        };
    print "Object car being created:\n";
    print "Name: $self->{name}\n";
    print "price: $self->{price}\n\n";    
        
    bless $self, $class;
    return $self;
}

sub speed_up{
    my $self = shift;
    my $acc = shift;
    $self->{speed} += $acc;
    return $self->{speed};
}

sub slow_down{
    my $self = shift;
    my $acc = shift;
    $self->{speed} -= $acc;
    return $self->{speed};
}
 
1;
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Here is an example of a belonging .pl file:

use strict;
use warnings;
use car;

my $speed;
my $auto = new car("Opel Vectra",50000);

$speed = $auto->speed_up(25);
print "Speed is: $speed km\n";

$speed = $auto->speed_up(10);
print "Speed is: $speed km\n";

$speed  = $auto->slow_down(20);
print "Speed is: $speed km\n";
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