Kevin

#!/usr/bin/perl

print roman(1968) . "\n";

sub roman
{
    @digits = reverse split('',shift,4);

    my @numerals = (
        ['','I','II','III','IV','V','VI','VII','VIII','IX'],
        ['','X','XX','XXX','XL','L','LX','LXX','LXXX','XC'],
        ['','C','CC','CCC','CD','D','DC','DCC','DCCC','CM'],
    );

    my $buf = 'M' x $digits[3];

    for ($i = scalar(@digits) - 1; $i >= 0; $i--) {
        $buf .= $numerals[$i]->[$digits[$i]];
    }
    return $buf;
}