perl 面向对象 new方法

[root@wx03 test]# cat Scan.pm
package Scan;
sub new{
    my $class = shift;
    my $self={
              'a'=>11,
              'b'=>22,
               'c'=>33
             };
    bless $self,$class;
    return $self;
            };
 
sub sum_all {
 
    my $self=shift;
    my ($c,$d,$e)=@_;
     return ($self->{a} + $self->{b} + $self->{c} + $c + $d + $e);
  };
1;
[root@wx03 test]# cat t12.pl
unshift(@INC,"/root/test");
use Scan ;
my $ua=Scan->new();
print $ua->sum_all(1,5,8);
[root@wx03 test]# perl t12.pl
80[root@wx03 test]# 
 
/*****************new 方法不定义内容:
 
[root@wx03 test]# cat Scan.pm
package Scan;
sub new{
    my $class = shift;
    my $self={};
    bless $self,$class;
    return $self;
            };
 
sub sum_all {
 
    my $self=shift;
    my ($c,$d,$e)=@_;
     return ( $c + $d + $e);
  };
1;
[root@wx03 test]# cat t12.pl
unshift(@INC,"/root/test");
use Scan ;
my $ua=Scan->new();
print $ua->sum_all(1,5,8);
[root@wx03 test]# perl t12.pl
14[root@wx03 test]#