php数字如何转换成大写文字

/**
 * 数字金额转换成中文大写金额,要求小数位数为两位
 * @param $num 要转换的小写数字或小写字符串
 * @return 大写金额字符串
 */
function get_amount($num){
 $c1 = "零壹贰叁肆伍陆柒捌玖";
 $c2 = "分角元拾佰仟万拾佰仟亿";
 $num = round($num, 2);
 $num = $num * 100;
 if (strlen($num) > 11) {
 return "数据太长，没有这么大的钱吧，检查下";
 }
 $i = 0;
 $c = "";
 while (1) {
 if ($i == 0) {
 $n = substr($num, strlen($num)-1, 1);
 } else {
 $n = $num % 10;
 }
 $p1 = substr($c1, 3 * $n, 3);
 $p2 = substr($c2, 3 * $i, 3);
 if ($n != '0' || ($n == '0' && ($p2 == '亿' || $p2 == '万' || $p2 == '元'))) {
 $c = $p1 . $p2 . $c;
 } else {
 $c = $p1 . $c;
 }
 $i = $i + 1;
 $num = $num / 10;
 $num = (int)$num;
 if ($num == 0) {
 break;
 }
 }
 $j = 0;
 $slen = strlen($c);
 while ($j < $slen) {
 $m = substr($c, $j, 6);
 if ($m == '零元' || $m == '零万' || $m == '零亿' || $m == '零零') {
 $left = substr($c, 0, $j);
 $right = substr($c, $j + 3);
 $c = $left . $right;
 $j = $j-3;
 $slen = $slen-3;
 }
 $j = $j + 3;
 }
 if (substr($c, strlen($c)-3, 3) == '零') {
 $c = substr($c, 0, strlen($c)-3);
 }
 if (empty($c)) {
 return "零元整";
 }else{
 return $c . "整";
 }
}