Welcome to the Monastery PerlMonks

### Comment on

 Need Help??
I didn't notice anyone using Roman numerals. I tested the applicable subroutine with lots of values, since I wrote it for this and hadn't used it before. If there are any bugs with it other than the design decision documented, please let me know. This might actually sneak into a project since I spent a good half hour designing, coding, testing, and commenting it.

Chris
```\$x = 'ii';
\$y = 'ii';

sub Roman {

=pod
This doesn't check for validity, as the
subtraction rule is always honored, even
for I before M if you want to do that.
Roman numerals generally allow I only before
V or X for the subtraction rule, X before
an L or a C, and C before a D or an M.

If you need to check validity, it'd be a
task suitable for a separate sub since
this one should be able to handle horked
but workable values by design, just in
case. Heck, this doesn't even check for
the existence of invalid characters. It
just ignores them.
=cut

my \$z = 0;
my @foo = uc(shift) =~ /(M+|D+|C+|L+|X+|V+|I+)/g;
my %value = (
'M' => 1000,
'D' => 500,
'C' => 100,
'L' => 50,
'X' => 10,
'V' => 5,
'I' => 1,
);
for ( my \$i = 0; \$i < scalar @foo; \$i++ ) {
my \$ch = substr \$foo[\$i], 0, 1;
my \$v = \$value{\$ch};
my \$nxt_ch = '';
my \$nxt_v = -1;
if ( defined ( \$foo[\$i + 1] ) ) {
\$nxt_ch = substr( \$foo[\$i + 1], 0, 1 );
\$nxt_v = \$value{\$nxt_ch};
}
foreach ( 1..length \$foo[\$i] ) {
if ( \$nxt_v > \$v ) {
\$z -= \$value{\$ch};
} else {
\$z += \$value{\$ch};
}
}
}
return \$z;
}

printf "The result is: %d\n", (Roman \$x) + (Roman \$y);

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

• Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
• Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
• Read Where should I post X? if you're not absolutely sure you're posting in the right place.
• Posts may use any of the Perl Monks Approved HTML tags:
a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
• You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
 For: Use: & & < < > > [ [ ] ]
• Link using PerlMonks shortcuts! What shortcuts can I use for linking?

Create A New User
Chatterbox?
and all is quiet...

How do I use this? | Other CB clients
Other Users?
Others browsing the Monastery: (7)
As of 2017-08-21 20:21 GMT
Sections?
Information?
Find Nodes?
Leftovers?
Voting Booth?
Who is your favorite scientist and why?

Results (325 votes). Check out past polls.

Notices?