title: cannot add another object into an array containing different objects
body: <p>Someone please help.</p>
  
  <p>I am a noob here who has just created an array to contain all my polyclinics object. Now I need to add in a user object (patientDetail object) into this array. But no matter how i modify the viewDidLoad method, something just seems not quite right.. i cannot populate all the points.. only when i remove all codes that deal with the user object then it works.. Some1 please take a look at the method below and advise? I need to add in the patientDetail object and populate it with the rest of the polyclinics...</p>
  
  <p>thanks for reading =(</p>
  
  <pre><code>- (void)viewDidLoad {
          [super viewDidLoad];
  
          _annotation2 = [[NSMutableArray alloc] init];
  
      CLLocation *userLoc = _mapView.userLocation.location;
          CLLocationCoordinate2D userCoordinate = userLoc.coordinate;
  
      NSLog(@"user latitude = %f",userCoordinate.latitude);
      NSLog(@"user longitude = %f",userCoordinate.longitude);
  
  
  
     _annotations=[[NSMutableArray alloc] init];
         _listOfPolyClinics = [[NSMutableArray alloc] init];
  
  PatientDetails *patientDetails = [[PatientDatabase database] 
                                    patientDetails:_nric];
  
  for (PolyClinics *polyclinics in [[PatientDatabase database] 
                                    polyClinics]){
      [_listOfPolyClinics addObject:polyclinics];
  }
  
  [_listOfPolyClinics addObject:patientDetails];
  
  
  
  for (PolyClinics *polyclinics1 in _listOfPolyClinics){
      MyAnnotation* myAnnotation=[[MyAnnotation alloc] init];
  
      if ([polyclinics1 isKindOfClass:[PatientDetails class]]){ 
          CLLocationCoordinate2D theCoordinate3;
          theCoordinate3.longitude = patientDetails.longitude;
          theCoordinate3.latitude = patientDetails.latitude;
  
          myAnnotation.coordinate = theCoordinate3;
          myAnnotation.title = _nric;
          myAnnotation.subtitle = [NSString        stringWithFormat:@"%i",patientDetails.category];
  
      }    
      else{
      CLLocationCoordinate2D theCoordinate;
      theCoordinate.longitude = polyclinics1.longtitude;
      NSLog(@"Halo");
      theCoordinate.latitude = polyclinics1.latitude;
      NSLog(@"bye");
  
  
      //myAnnotation.pinColor = MKPinAnnotationColorPurple;
      myAnnotation.coordinate = theCoordinate;
      myAnnotation.title = polyclinics1.name;
      myAnnotation.subtitle = [NSString stringWithFormat:@"%i",polyclinics1.telephone];
      }
      [_mapView addAnnotation:myAnnotation];
      [_annotation2 addObject:myAnnotation];
  
  }
  </code></pre>