C:\test>p1
[0] Perl> use Devel::Size qw[ size total_size ];;
[0] Perl> @a = 1 .. 10;;
[0] Perl> print size( \@a ), ':', total_size( \@a );;
256 : 496
[0] Perl> print $#a;;
9
[0] Perl> print size( \@a ), ':', total_size( \@a );;
440 : 680

C:\test>p1
[0] Perl> use Devel::Size qw[ size total_size ];;
[0] Perl> @a = 1 .. 10;;
[0] Perl> print size( \@a ), ':', total_size( \@a );;
256 : 496
[0] Perl> $x = 0+$#a;;
[0] Perl> print size( \@a ), ':', total_size( \@a );;
432 : 672

C:\test>p1
[0] Perl> use Devel::Size qw[ size total_size ];;
[0] Perl> @a = 1 .. 10;;
[0] Perl> print size( \@a ), ':', total_size( \@a );;
256 : 496
[0] Perl> $x = ${ \$#a };;
[0] Perl> print size( \@a ), ':', total_size( \@a );;
432 : 672