D = 500， L = 50。

DCD)， //$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。

X = 10，XC，$return); } // echo dec2romen(1981); // Function to get the decimal value of a roman string: function roman2dec($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。

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); ? 。

V = 5， $v) : $k . $old_k; $old_k = $k; } // Replace some spacial cases and return the string: return str_replace(array(VIV， I = 1 ); // Calculate the needed roman figures: foreach($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。

C = 100， D = 500， V = 5，LXL， X = 10， L = 50，CM)，array(IX， C = 100， 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 ?php // Function that calculates the roman string to the given number: function dec2roman($f) { // Return false if either $f is not a real number，。