首页 / 网页编程 / PHP / php实现阿拉伯数字和罗马数字相互转换的方法

<?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）;?>