sub next_prime_iterator {
   my $num = shift(@_);
   return 3   if  $num < 3;
   do { $num += 2 } until is_prime($num);
   return $num;
}

sub is_prime {
   my $guess = shift(@_);

   my $divisor = 3;
   my $quotient;
   while(1) {
       $quotient= $guess / $divisor;
       return 1   if  $quotient < $divisor;
       return 0   if  int($quotient) == $quotient;
       $divisor += 2;
   }
}

##</code><code>##

my $x= 1+~0;
$x *= 2 while $x != $x+1;
$x /= 2;
my $y= $x;
for( 1..5 ) {
    $x++;
    print $x-$y, " ", $x%3, " ", $x/3-int($x/3), "; ";
}
print $/
__END__
1 0 0.75; 2 0 0; 3 2 0.25; 4 2 0.75; 5 1 0;