not sure whats causing these errors

 #import "ViewController.h"




@interface ViewController ()

@end

@implementation ViewController
- (void)viewDidLoad {
  [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
 // Dispose of any resources that can be recreated.
}


@end

I'm not sure what I changed or how to fix these errors:

Cannot find interface declaration for 'ViewController'; View controller cannot use 'super because it is not a root class