// I have included a few steps in here to show the flow I normally do to get things working.
// Keep in mind I'm still a massive noob so there may be a better way to do all of this :/


// ...
// Class definition and imports

// STEP 1: Declare vars in the controller @interface
@interface MapViewController : UIViewController <MKMapViewDelegate, UISearchBarDelegate> {
    // ...

    // Interface objects
    MKMapView *mapView;
    UISearchBar *searchBar;

    // ...
    
    // Result objects
    NSMutableArray *results;
    NSMutableData *requestData;

}

// STEP 2: Declare properties of all above declared vars

// Interface objects
@property (nonatomic, retain) MKMapView *mapView;
@property (nonatomic, retain) UISearchBar *searchBar;

// Result objects
@property (nonatomic, retain) NSMutableArray *results;
@property (nonatomic, retain) NSMutableData *requestData;

// ...
// Function definitions etc.