php实现阿拉伯数字和罗马数字相互转换的方法

本文实例讲述了php实现阿拉伯数字和罗马数字相互转换的方法。分享给大家供大家参考。具

本文实例讲述了php实现阿拉伯数字和罗马数字相互转换的方法。分享给大家供大家参考。具体如下：

<?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); 
?>

希望本文所述对大家的php程序设计有所帮助。