Math
|
|
|
|
<?PHP
/*
Decimal <--> Roman 1.1
Written by: Rasmus Rimestad
Email: rasmusr@online.no
Homepage: http://dikt.cjb.net
Written: XXIV.VII.MMI
This file includes two functions
string dec2roman (integer $number)
where $number is a number you want to convert to a roman one.
integer roman2dec (string $linje)
where $linje is the roman number you want to conver to an integer.
*/
function dec2roman ($number) {
# Making input compatible with script.
$number = floor($number);
if($number < 0) {
$linje = "-";
$number = abs($number);
}
# Defining arrays
$romanNumbers = array(1000, 500, 100, 50, 10, 5, 1);
$romanLettersToNumbers = array("M" => 1000, "D" => 500, "C" => 100, "L" => 50, "X" => 10, "V" => 5, "I" => 1);
$romanLetters = array_keys($romanLettersToNumbers);
# Looping through and adding letters.
while ($number) {
for($pos = 0; $pos <= 6; $pos++) {
# Dividing the remaining number with one of the roman numbers.
$dividend = $number / $romanNumbers[$pos];
# If that division is >= 1, round down, and add that number of letters to the string.
if($dividend >= 1) {
$linje .= str_repeat($romanLetters[$pos], floor($dividend));
# Reduce the number to reflect what is left to make roman of.
$number -= floor($dividend) * $romanNumbers[$pos];
}
}
}
# If I find 4 instances of the same letter, this should be done in a different way.
# Then, subtract instead of adding (smaller number in front of larger).
$numberOfChanges = 1;
while($numberOfChanges) {
$numberOfChanges = 0;
for($start = 0; $start < strlen($linje); $start++) {
$chunk = substr($linje, $start, 1);
if($chunk == $oldChunk && $chunk != "M") {
$appearance++;
} else {
$oldChunk = $chunk;
$appearance = 1;
}
# Was there found 4 instances.
if($appearance == 4) {
$firstLetter = substr($linje, $start - 4, 1);
$letter = $chunk;
$sum = $firstNumber + $letterNumber * 4;
$pos = array_search($letter, $romanLetters);
# Are the four digits to be calculated together with the one before? (Example yes: VIIII = IX Example no: MIIII = MIV
# This is found by checking if the digit before the first of the four instances is the one which is before the digits in the order
# of the roman number. I.e. MDCLXVI.
if($romanLetters[$pos - 1] == $firstLetter) {
$oldString = $firstLetter . str_repeat($letter, 4);
$newString = $letter . $romanLetters[$pos - 2];
} else {
$oldString = str_repeat($letter, 4);
$newString = $letter . $romanLetters[$pos - 1];
}
$numberOfChanges++;
$linje = str_replace($oldString, $newString, $linje);
}
}
}
return $linje;
}
function roman2dec ($linje) {
# Fixing variable so it follows my convention
$linje = strtoupper($linje);
# Removing all not-roman letters
$linje = ereg_replace("[^IVXLCDM]", "", $linje);
print("$linje = $linje<br>");
# Defining variables
$romanLettersToNumbers = array("M" => 1000, "D" => 500, "C" => 100, "L" => 50, "X" => 10, "V" => 5, "I" => 1);
$oldChunk = 1001;
# Looping through line
for($start = 0; $start < strlen($linje); $start++) {
$chunk = substr($linje, $start, 1);
$chunk = $romanLettersToNumbers[$chunk];
if($chunk <= $oldChunk) {
$calculation .= " + $chunk";
} else {
$calculation .= " + " . ($chunk - (2 * $oldChunk));
}
$oldChunk = $chunk;
}
# Summing it up
eval("$calculation = $calculation;");
return $calculation;
}
# Implementation of the array_search function. Works only with numerical arrays.
function array_search($searchString, $array) {
foreach ($array as $content) {
if($content == $searchString) {
return $pos;
}
$pos++;
}
}
?>
|
|
|
Usage Example
|
|
|
Rate This Script
|
|
|
|
Store
Your email: