use Benchmark qw(cmpthese);

my $size = $ARGV[0] || 1000;

my @array = (1..$size);

sub undef_it {
	undef @array;
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

sub empty_it {
	@array = ();
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

sub empty_elements {
	undef $_ for @array;
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

sub assign_list_of_undefs {
	@array = (undef) x $size;
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

sub undef_resize {
	undef @array; $#array = $size;
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

sub empty_resize {
	@array = (); $#array = $size;
	$array[$_]=$_ foreach (0..$size-1);
	return;
}

cmpthese( -10, {
	undef_it => \&undef_it,
	empty_it => \&empty_it,
	empty_elements => \&empty_elements,
	assign_list_of_undefs => \&assign_list_of_undefs,
	undef_resize => \&undef_resize,
	empty_resize => \&empty_resize,
});