use Benchmark;
use strict;

sub arrayInit {
	foreach (1..1000) {
		my @list;
		foreach (1..10) {
			push @list, $_;
		}
	}
}

sub arrayUndef {
	my @list;
	foreach (1..1000) {
		foreach (1..10) {
			push @list, $_;
		}
		undef @list;
	}
}

sub arrayEmpty {
	my @list;
	foreach (1..1000) {
		foreach (1..10) {
			push @list, $_;
		}
		@list = ();
	}
}

sub scalarInit {
	foreach (1..1000) {
		my $sum;
		foreach (1..10) {
			$sum += $_;
		}
	}
}

sub scalarUndef {
	my $sum;
	foreach (1..1000) {
		foreach (1..10) {
			$sum += $_;
		}
		undef $sum;
	}
}

sub scalarEmpty {
	my $sum;
	foreach (1..1000) {
		foreach (1..10) {
			$sum += $_;
		}
		$sum = 0;
	}
}

timethese 1000, {
	arrayInit => \&arrayInit,
	arrayUndef => \&arrayUndef,
	arrayEmpty => \&arrayEmpty,
	scalarInit => \&scalarInit,
	scalarUndef => \&scalarUndef,
	scalarEmpty => \&scalarEmpty,
}
__END__

Benchmark: timing 1000 iterations of arrayEmpty, arrayInit, arrayUndef, scalarEmpty, scalarInit, sca
larUndef...
arrayEmpty: 15 wallclock secs (13.97 usr +  0.00 sys = 13.97 CPU) @ 71.58/s (n=1000)
 arrayInit: 13 wallclock secs (13.45 usr +  0.00 sys = 13.45 CPU) @ 74.35/s (n=1000)
arrayUndef: 16 wallclock secs (15.70 usr +  0.00 sys = 15.70 CPU) @ 63.68/s (n=1000)
scalarEmpty:  9 wallclock secs ( 9.30 usr +  0.02 sys =  9.32 CPU) @ 107.26/s (n=1000)
scalarInit: 10 wallclock secs ( 9.36 usr +  0.01 sys =  9.37 CPU) @ 106.68/s (n=1000)
scalarUndef: 10 wallclock secs ( 9.43 usr +  0.00 sys =  9.43 CPU) @ 106.01/s (n=1000)