Re: why the array index has to start at 0??

[citromatik]

It hasn't:

use strict;
use warnings;
use feature qw/ :5.10 /;

my @ar = qw/1 2 3 4 5/;

$[=1;

say $ar[$_] for (1..@ar);

Although you may not want to do that. See perlvar