编写一个实现文件夹的递归遍历的函数

function dir_recurse($dir)
{
    $i = 1;
    if($handle = opendir($dir)) {
        while(false !== ($file = readdir($handle))) {
            if($file != "."&& $file != ".." ) {
                if(is_dir($dir."/".$file) == true) {
                    $fullpath = $dir."/".$file;
                    dir_recurse($fullpath);
                    echo "$fullpath\n";
                    $i++;
                }else {
                    $fullpath = $dir."/".$file;
                    echo "$fullpath\n";
                    $i++;
                }
            }
        }
        closedir($handle);
    }
}