地址指针的使用

NSFileManager *fileManager = [NSFileManager defaultManager];

    //创建缩略图文件夹

    NSString *folderPath = [path stringByAppendingPathComponent:@"temp"];

    BOOL  isDir0 = NO;

    BOOL existed0 = [fileManager fileExistsAtPath:folderPath isDirectory:&isDir0];

    if ( !(isDir0 == YES && existed0 == YES) ){

        [fileManager createDirectoryAtPath:folderPath withIntermediateDirectories:YES attributes:nil error:nil];

    }