Subroutine that takes average of one or more arrays - arrays

Question

I'm working on a subroutine that takes the average of 1 or more arrays. I would like to do this without using a module.
use strict;
use warnings;
use List::Util 'sum';
my #w = (0, 2);
my #x = (1, 3);
my #y = (2, 2);
my #z = (1, 1);
# the average of these four arrays is (1,2) since
# (0+1+2+1)/4 = 1 and (2+3+2+1)/4 = 2
my #arrays = \(#w, #x, #y, #z);
my #avg;
# this is the way to do it using the module
for my $i (0..$#w) {
$avg[$i] = sum(map $_->[$i], #arrays) / #arrays;
}
print "#avg\n";
# my way of doing it without module
#avg;
for my $i (0..$#w) {
$avg[$i] = prod_sum(map $_->[$i], \#arrays) / #arrays;
}
print "#avg\n";
# subroutines
sub prod_sum{
my $o = $_[0];
my $arr_ref = $_[1];
my $array_ref;
foreach my $row (#$arr_ref){
foreach my $cell (#$row) {
push(#{ $array_ref }, $_);
}
}
my $sum = $o + the_sum($array_ref);
return $sum;
}
sub the_sum{
my $sum = 0;
for ( #{$_[0]} ) {
$sum += $_;
}
return $sum;
}
output
1 2
[pair of really random big numbers]
The first output is correct. It displays the average of all of the arrays. The second output is completely wrong. How do I do this without using a module?

Answer 1

I propose this solution:
use strict;
use warnings;
my #w = (0, 2);
my #x = (1, 3);
my #y = (2, 2);
my #z = (1, 1);
my #arrays = \(#w, #x, #y, #z);
my ($x, $y) = (0, 0);
foreach my $arr(#arrays) {
$x += $arr->[0];
$y += $arr->[1];
}
my #result = ( $x / #arrays, $y / #arrays);
print "(#result)", "\n"; # <---- prints (1 2)

Answer 2

You think sum is being passed two variables, it is not. It is only being passed an array. Modify your prod_sum to expect only an array (and replace \#arrays in the call of prod_sum to be just #arrays). Or you can use this:
sub sum {
return 0 if $#_ < 0;
my $head = shift;
return $head + sum(#_);
}
The above is a recursive subroutine that will sum an array.
Note: if your array has more then 100 element, use warnings will emit a deep recursion warning. For more on that topic, see here