=head1

For newcomers to coding, it's a good idea to write the comments first -
they're a sort of flowchart of pseudo code into which you can fill the
answers.

Any of you're writing a very early program with your first loop -
remember that there are things you do before you start repeating
anything - setups, etc
        -- THEY GO ABOVE THE LOOP
there are things that you want to repeat
        -- THEY GO IN THE LOOP
and there are things to do at the end
        -- THEY GO AFTER THE LOOP

This program also shows you how to use an "accumulator" - that's a
variable that you set to zero at the start and then you add in numbers
as you get them, thus ending up with a sum at the end. In Perl, it's
an ordinary scalar variable - it's just the use within the loop, where
it keeps changing, that may be new to you.

=cut

# the bit before

print "What's the first amount? ";
chop ($amount = <STDIN>);
$sofar = $amount;
$howmany = 1;

# repeated stuff

while ($amount > 0) {

        print "What's the next amount? ";
        chop ($amount = <STDIN>);
        if ($amount > 0) {
                $sofar += $amount;
                $howmany++;
        }
}

# final results

print "Total spend is $sofar\n";
print "Input count: $howmany\n";

__END__

Sample output:

Dorothy-2:j10p grahamellis$ perl summer
What's the first amount? 4
What's the next amount? 5
What's the next amount? 12
What's the next amount? 3
What's the next amount? 4
What's the next amount? 0
Total spend is 28
Input count: 5
Dorothy-2:j10p grahamellis$