Hi Molks!

I'm just starting to get to grips with the OO features of Perl and i found this basic example on the forums Re: Algorithm::Treap and i've been playing around with it, which has resulted in a few questions

First of all, is there a preferred style for "new" constructors? Specifically one which will be taking hash value/key pairs as attributes?

Secondly, is there a way to tell how many objects have been created/exist in a particular class?

And lastly, what is the best way to access individual object attributes? Always through a method or can you access them directly?

Here's the basic code i was messing around with. As Always, any help and comments greatly appreciated!

#! /gte/bin/perl -w
use strict;
use warnings;

my $obj=Numbers->new('num1'=>7, 'num2'=>2);

print "The object attribute num1 is ",$obj->dump('num1'),"\n";
print "The object attribute num2 is ",$obj->dump('num2'),"\n";
$obj->add_nums();
print "The add result is ",$obj->dump('result'),"\n";
$obj->subtract_nums();
print "The subtract result is ",$obj->dump('result'),"\n";

package Numbers;        # This is the class

sub new {
  my $class=shift;
  my %params=@_;
  my $self={};
  $self->{$_}=$params{$_} foreach keys(%params);
  bless($self, $class);
  return $self;
}

sub add_nums {
  my $self=shift;
  $self->{result}=$self->{num1}+$self->{num2};
  return $self->{result};
}


sub subtract_nums {
  my $self=shift;
  $self->{result}=$self->{num1}-$self->{num2};
  return $self->{result};
}

sub change_nums {
  my $self=shift;
  my %params=@_;
  $self->{$_}=$params{$_} foreach keys(%params);
  return $self;
}

sub dump {
  my $self=shift;
  my $val=shift;
  return $self->{$val};
}

1;

__END__
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