PHPで整数をローマ数字に変換するにはどうすればよいですか? (コード例)

<?php
header("content-type:text/html;charset=utf-8");
//将数字转换为罗马表示形式
function numberToRoman($num)  
{ 
    // Be sure to convert the given parameter into an integer
    $n = intval($num);
    $result = &#39;&#39;; 
 
    // Declare a lookup array that we will use to traverse the number: 
    $lookup = array(
        &#39;M&#39; => 1000, &#39;CM&#39; => 900, &#39;D&#39; => 500, &#39;CD&#39; => 400, 
        &#39;C&#39; => 100, &#39;XC&#39; => 90, &#39;L&#39; => 50, &#39;XL&#39; => 40, 
        &#39;X&#39; => 10, &#39;IX&#39; => 9, &#39;V&#39; => 5, &#39;IV&#39; => 4, &#39;I&#39; => 1
    ); 
 
    foreach ($lookup as $roman => $value)  
    {
        // Look for number of matches
        $matches = intval($n / $value); 
 
        // Concatenate characters
        $result .= str_repeat($roman, $matches); 
 
        // Substract that from the number 
        $n = $n % $value; 
    } 
    return $result; 
} 
echo &#39;整数数字转换为罗马数字：<br><br>&#39;;
// VIII
echo &#39;数字8：&#39;.numberToRoman(8).&#39;<br>&#39;;
// CXXIII
echo &#39;数字123：&#39;.numberToRoman(123).&#39;<br>&#39;;
// MMCCCLV
echo &#39;数字2355：&#39;.numberToRoman(2355).&#39;<br>&#39;;
// MMMMCMXCIX
echo &#39;数字4999：&#39;.numberToRoman(4999).&#39;<br>&#39;;
?>

<?php
use Romans\Filter\IntToRoman;

$filter = new IntToRoman();
$result = $filter->filter(1999);
echo $result;
?>

MCMXCIX

<?php
use Romans\Filter\RomanToInt;

$filter = new RomanToInt();
$result = $filter->filter(&#39;MCMXCIX&#39;);
echo $result;
?>

1999