crunch-it: little benchmark in Perl

gistfile1.pl

#!/usr/bin/env perl

use Modern::Perl;
#use diagnostics;
use List::Util qw/max min sum/;

# TODO: more of the following code needs to be put into functions

if (@ARGV != 1) {
    say "Please pass exactly one arg: the number of";
    say "random strings to be generated for this run.";
    exit;
}
my $num_strings_to_generate = $ARGV[0];

my $DEBUG = 0;

my @sample_chars = ('a' .. 'l', 0 .. 9);
my @random_strings;

sub make_random_string {
    # take $n items from list @a, and join them
    # together into a string.
    my ($n, @a) = @_;
    my $accum = '';
    for my $i (1 .. $n) {
        my $r = $a[ rand(@a) ];
        $accum .= $r;
    }
    return $accum;
}

for (1 .. $num_strings_to_generate) {
    push @random_strings, make_random_string(10, @sample_chars);
}

if ($DEBUG) { say "DEBUG: random strings: @random_strings"; }

my @nums = ();
my %num_chars = ();
for (3 .. 10) { $num_chars{$_} = 0; }

sub show_num_chars {
    my ($h_ref) = @_;
    for my $k (sort keys %{$h_ref}) {  # sort these an nums, not strs! XXX
        say "    $k: ", ${$h_ref}{$k};
    }
}

for my $s (@random_strings) {
    if ($s =~ m/([1-9]\d{2,})/) {
        $num_chars{ length($1) }++;
        push @nums, $1;
    }
}

if ($DEBUG) { say "DEBUG, nums: @nums"; }

say "Generated ", scalar(@random_strings), " random strings.";
say "Found ", scalar @nums, " numbers.";
say "Min: ", min(@nums), '.';
say "Max: ", max(@nums), '.';
say "Distribution:";
show_num_chars(\%num_chars);

my @logs = ();
for my $n (@nums) { push @logs, log($n); }
if ($DEBUG) { say "DEBUG, logs: @logs"; }

my $avg = sum(@logs) / @logs;

say "Avg of natural logs:", sprintf("%.2f", $avg);
say '-' x 42;