#!/usr/bin/env perl -l

use strict;
use warnings;

{
    my $val = 10;

    print "INIT: $val";
    show_value($val);
    change_value(\$val, 200);
    show_value($val);
    unrelated_value();
    show_value($val);
    print "LAST: $val";
}

sub show_value {
    my ($val) = @_;

    print '* Show Value';
    print "Value: $val";

    return;
}

sub change_value {
    my ($val_ref, $new_value) = @_;

    print "* Change Value: $$val_ref to $new_value";
    show_value($$val_ref);
    $$val_ref = $new_value;
    show_value($$val_ref);

    return;
}

sub unrelated_value {
    my $val = 42;

    print '* Unrelated Value';
    change_value(\$val, 999);

    return;
}