@eins = (1..10,12);
@zwei = (9..15);

@drei =  schnitt(\@eins, \@zwei);

print "1: ", join(",",@eins), "\n";
print "2: ", join(",",@zwei), "\n";
print "3: ", join(",",@drei), "\n";

sub schnitt 
  {
  my @final = ();
  my ($i, $j);
  # Kontrollausgabe
  print "< ", join(",",@_), " >\n";
  
  # Schnittmenge ermitteln
  my ($first, $second) = @_;
  foreach $i (@$first) 
    {
    foreach $j (@$second) 
      {
      if ($i eq $j) 
        {
        push @final,$j;
        last;
        }
      }
    }
  return @final;
  }