program_23_good.pl

#!/usr/bin/env perl

# [[[ PREPROCESSOR ]]]
# <<< EXECUTE_SUCCESS: 'size of $foo is 10' >>>

# [[[ HEADER ]]]
use RPerl;
use strict;
use warnings;
our $VERSION = 0.001_000;

# [[[ CRITICS ]]]
## no critic qw(ProhibitUselessNoCritic ProhibitMagicNumbers RequireCheckedSyscalls)  # USER DEFAULT 1: allow numeric values & print operator
## no critic qw(RequireInterpolationOfMetachars)  # USER DEFAULT 2: allow single-quoted control characters & sigils

# [[[ OPERATIONS ]]]

my integer $size_max_half = 5;
my number_arrayref $foo->[($size_max_half * 2) - 1] = undef;
print 'size of $foo is ' . ( scalar @{$foo} ) . "\n";