How php converts Arabic and Roman numerals

This article describes how php converts Arabic and Roman numerals. it involves php string operations related skills and has some reference value, for more information about how to convert Arabic and Roman numerals in php, see the following example. Share it with you for your reference. The details are as follows:

<?php// Function that calculates the roman string to the given number:function dec2roman($f){ // Return false if either $f is not a real number,  //$f is bigger than 3999 or $f is lower or equal to 0:    if(!is_numeric($f) || $f > 3999 || $f <= 0) return false; // Define the roman figures:  $roman = array(  'M' => 1000,  'D' => 500,  'C' => 100,  'L' => 50,  'X' => 10,  'V' => 5,  'I' => 1  ); // Calculate the needed roman figures:  foreach($roman as $k => $v)  if(($amount[$k] = floor($f / $v)) > 0)  $f -= $amount[$k] * $v; // Build the string:  $return = '';  foreach($amount as $k => $v)  {   $return .= $v <= 3 ? str_repeat($k, $v) : $k . $old_k;   $old_k = $k;    } // Replace some spacial cases and return the string:  return str_replace(array('VIV','LXL','DCD'),array('IX','XC','CM'),$return);}// echo dec2romen(1981);// Function to get the decimal value of a roman string:function roman2dec($str = ''){ // Return false if not at least one letter is in the string:  if(is_numeric($str)) return false; // Define the roman figures:  $roman = array(  'M' => 1000,  'D' => 500,  'C' => 100,  'L' => 50,  'X' => 10,  'V' => 5,  'I' => 1  ); // Convert the string to an array of roman values:  for($i = 0; $i < strlen($str); $i++)   if(isset($roman[strtoupper($str[$i])]))  $values[] = $roman[strtoupper($str[$i])]; // Calculate the sum of that array:  $sum = 0;  while($current = current($values))  {   $next = next($values);   $next > $current ? $sum += $next - $current + 0 * next($values) : $sum += $current;  } // Return the value:  return $sum;}// echo roman2dec(IX);  ?>

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