#!/usr/bin/env perl

use strict;
use warnings;
use Time::HiRes qw(time);
use Devel::Size qw(size);


my $array_size = 5_000_000;

my @array0;
my @array1;

print "Testing preallocation.\n";
my $t0 = time();
$#array0 = $array_size-1;
for (my $i = 0; $i < $array_size; $i++) {
    $array0[$i] = $i;
}
my $t0_delta = time() - $t0;
print scalar(@array0), " elements. Last element value is $array0[-1]\n";
printf "Array size is %-0.2f megabytes\n", size(\@array0)/1024/1024;
printf "With preallocation: %-0.4f seconds\n", $t0_delta;

print "\nTesting without preallocation.\n";
my $t1 = time();
for (my $j = 0; $j < $array_size; $j++) {
    $array1[$j] = $j;
}

my $t1_delta = time() - $t1;
print scalar(@array1), " elements. Last element value is $array1[-1]\n";
printf "Array size is %-0.2f megabytes\n", size(\@array1)/1024/1024;
printf "Without preallocation: %-0.4f seconds\n", $t1_delta;