Annotations on MapView: Coordinates - objective-c

Question

I have two NSStrings (address, and key) which contain the coordinates (longitude and latitude) in form of numbers (34,56789...):
NSString *key = [allKeys objectAtIndex:i];
NSObject *obj = [DictionaryMap objectForKey:key];
NSString *address = [NSString stringWithFormat:#"%#", obj];
CLLocationCoordinate2D anyLocation;
anyLocation.latitude = [address doubleValue];
anyLocation.longitude = [key doubleValue];
MKPointAnnotation *annotationPoint2 = [[MKPointAnnotation alloc] init]; annotationPoint2.coordinate = anyLocation;
annotationPoint2.title = #"Event";
annotationPoint2.subtitle = #"Microsoft's headquarters2";
[mapView addAnnotation:annotationPoint2];
...But I can't understand why it doesn't plot in the same point as the coordinates written. I think this doesn't work:
[address doubleValue]
So I tried replacing it with:
location.latitude = NSNumber/NSString
but it gives an error.
UPDATE:
IN VIEW DID LOAD:
UILongPressGestureRecognizer *longPressGesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(handleLongPressGesture:)];
[self.mapView addGestureRecognizer:longPressGesture];
[mapView.userLocation setTitle:#"I am here"];
..then...
-(void)handleLongPressGesture:(UIGestureRecognizer*)sender {
// This is important if you only want to receive one tap and hold event
if (sender.state == UIGestureRecognizerStateEnded)
{
[self.mapView removeGestureRecognizer:sender];
}
else
{
// Here we get the CGPoint for the touch and convert it to latitude and longitude coordinates to display on the map
CGPoint point = [sender locationInView:self.mapView];
CLLocationCoordinate2D locCoord = [self.mapView convertPoint:point toCoordinateFromView:self.mapView];
// Then all you have to do is create the annotation and add it to the map
MKPointAnnotation *annotationPoint = [[MKPointAnnotation alloc] init]; annotationPoint.coordinate = locCoord;
annotationPoint.title = #"Microsoft";
annotationPoint.subtitle = #"Microsoft's headquarters";
[mapView addAnnotation:annotationPoint];
NSString *latitude = [[NSString alloc] initWithFormat:#"%f",locCoord.latitude];
NSString *longitude = [[NSString alloc] initWithFormat:#"%f", locCoord.longitude];
NSLog(latitude);
NSLog(longitude);
[[NSUserDefaults standardUserDefaults]setObject:latitude forKey:#"FolderLatitude"];
[[NSUserDefaults standardUserDefaults]setObject:longitude forKey:#"FolderLongitude"];
}
}
...I then save the coordinates in a JSON file and then read them from the file.

Answer 1

Print out the values that you are setting for lat/lon. It sounds like these values are not being converted to double properly. If the strings are not in "xxx.xxx" format then they will not convert to doubles properly when you call doubleValue.

Answer 2

Finally I understood: This is the correct way to make it work:
NSString *myString = (string initialization here)
float stringFloat = [myString floatValue];
anyLocation.longitude = stringFloat;