实现数字转人民币大写

function numToRmb($num){
    $rmbNum = ['零','壹','贰','叁','肆','伍','陆','柒','捌','玖'];
    $rmbUnit = ['分','角','元','拾','佰','仟','万','拾','佰','仟','亿','拾','佰','仟','万','拾','佰','仟'];
    //数字预处理
    if($num == '' || $num == 0){
        return '数字错误 -1';
    }else {
        $num = number_format($num, 2, '.', '')*100;
    }
    if (strlen(number_format($num, 0, '', '')) > 18) {
        return '输入的金额不得超过千万亿！';
    }
    $rmb = '';
    for ($out1 = 0 ; $out1 < strlen(number_format($num, 0, '', '')); $out1++) {
        $numRmb = $rmbNum[substr(number_format($num, 0, '', ''), $out1, 1)];
        $unit = $rmbUnit[strlen(number_format($num, 0, '', ''))-$out1-1];
        $rmb = $rmb.$numRmb.$unit;
    }
    $rmbStrlen = strlen($rmb);
    for ($out2=0; $out2 < $rmbStrlen; $out2=$out2+3) {
        $tempRmb = substr($rmb, $out2, 6);
        if ($tempRmb=='零元'||$tempRmb=='零万'||$tempRmb=='零亿') {
            $left = substr($rmb, 0, $out2);
            $right = substr($rmb, $out2+3);
            $rmb = $left.$right;
            $out2 = $out2 - 3;
            $rmbStrlen = $rmbStrlen - 3;
        }elseif ($tempRmb=='零拾'||$tempRmb=='零佰'||$tempRmb=='零仟') {
            $left = substr($rmb, 0, $out2+3);
            $right = substr($rmb, $out2+6);
            $rmb = $left.$right;
            $out2 = $out2 - 3;
            $rmbStrlen = $rmbStrlen - 3;
        }elseif ($tempRmb=='零分'||$tempRmb=='零角') {
            $left = substr($rmb, 0, $out2);
            $right = substr($rmb, $out2+6);
            $rmb = $left.$right;
            $out2 = $out2 - 6;
            $rmbStrlen = $rmbStrlen - 6;
        }
        if ($tempRmb=='零零') {
            $left = substr($rmb, 0, $out2);
            $right = substr($rmb, $out2+3);
            $rmb = $left.$right;
            $out2 = $out2 - 3;
            $rmbStrlen = $rmbStrlen - 3;
        }
        if(substr($rmb,strlen($rmb)-3)=='元') {
            $rmb = $rmb.'整';
        }
    }
    return $rmb;
}