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 == &#39;零元&#39; || $m == &#39;零万&#39; || $m == &#39;零亿&#39; || $m == &#39;零零&#39;) {
            $left = substr($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) == &#39;零&#39;) {
        $c = substr($c, 0, strlen($c)-3);
    }
    if (empty($c)) {
        return "零元整";
    }else{
        return $c . "整";
    }
}