Actually you can call a sub like so: sub_name()

Behold the difference in the output of the following snippet

print "Now testing with the ampersand\n";
&ampersand('arg1', 'arg2');

print "Now testing with the ampersand, but with 'blank' arguments\n";
&ampersand_blank_arg;

print "Now testing without the ampersand\n";
no_ampersand('arg1', 'arg2');

sub ampersand {
    &two;
}

sub ampersand_blank_arg {
    &two();
}

sub no_ampersand {
    two();
}

sub two {
    print "@_\n";
}


__OUTPUT___
Now testing with the ampersand
arg1 arg2
Now testing with the ampersand, but with 'blank' arguments

Now testing without the ampersand
[download]

The side effect obviously visible with using the ampersand is that it passes the @_ from the sub that called it. And of course, this could easily be thwarted by just putting the empty parens behind the sub name (as demonstrated by ampersand_blank_arg). But I also read on this site ((tye)Re: A question of style) that using the ampersand screws with prototypes.

In the beginning, I used them all the time. Then I pulled my hair out for about a week because I accidentally happened upon the @_ problem. I then started to put the empty parens behind them. But I'm human. I forgot sometimes and I'd kick my self everytime I found one that I missed. Then I found out that you don't need the ampersand if you use the parens and if you forget the parens, you get a bareword error. I love it when Perl tells me I've screwed up.

The &-form of sub call is obsolete and should never be used nowadays unless when one really know what he's doing.

Lies! There is no other way to call a sub. Stop trying to confuse the newbie.

Update: re-reading the code I realize that obviously the OP's problem may just be that he calls his sub out of the while loop, then he uses the return value of that sub, saved into a variable, every time it is needed inside the loop. OTOH there are IMHO bigger problems with his code, as signalled above.

Translation: The problem was too tough for you, so you resorted to attacking it for stylistic differeneces. Shame on you.