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#!/usr/bin/perl
# https://perlweeklychallenge.org/blog/perl-weekly-challenge-002/
# Challenge #2
# Write a script that can convert integers to and from a base35 representation,
# using the characters 0-9 and A-Y. Dave Jacoby came up with nice description about base35,
# in case you needed some background.
# https://gist.github.com/jacoby/764bb4e8a5d3a819b5fbfa497fcb3454
#Usage
# ch-2.pl --to-base35 <base-10-number>
# ch-2.pl --from-base35 <base-35-number>
use strict;
my @base = (0..9,'A' .. 'Y');
print to_base35($ARGV[1]) if ($ARGV[0] eq '--to-base35');
print from_base35($ARGV[1]) if ($ARGV[0] eq '--from-base35');
sub to_base35 {
my ($i) = @_;
return 0 if ($i == 0);
my $sign = ($i =~ s/-//) ? '-' : '';
my $result;
while ($i > 0) {
$result .= $base[$i % @base];
$i = int($i / @base);
}
return $sign . reverse $result;
}
sub from_base35 {
my ($t) = @_;
$t = reverse $t;
my $sign = ($t =~ s/-//) ? '-' : '';
my $result = 0;
for my $i (0..length($t)-1){
my $c = substr($t, $i, 1);
my ($index) = grep { $base[$_] eq $c } (0 .. @base-1);
$result += $index * ( @base ** $i );
}
return $sign . $result;
}
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