How PHP realizes the conversion between Arabic and Roman numerals _php skills

The example in this article describes how PHP realizes the conversion of Arabic and Roman numerals to each other. Share to everyone for your reference. as follows:

<?php//Function that calculates "Roman string to" given Number:function Dec2roman ($f) {//return FALSE if E Ither $f is isn't a real number,//$f are 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: $roman = array (' M ' => 1000, ' D ' =>, ' C ' =>, ' L ' =>, ' X ' =
 >, ' V ' => 5, ' I ' => 1); Calculate the needed Roman Figures:foreach ($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-string:if (Is_numeric ($STR)) return false; Define The Roman figures: $roman = array (' M ' => 1000, ' D ' =>, ' C ' =>, ' L ' =>, ' X ' =
 >, ' V ' => 5, ' I ' => 1); Convert the string to an array of Roman values:for ($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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