title: how can i check NSNumber is null?
body: <pre><code> NSDictionary *regionDict = (NSDictionary *) region;
              NSNumber *lat = [regionDict objectForKey:@"lat"];
              //[latitude addObject:lat];
              NSNumber *lng = [regionDict objectForKey:@"lng"];
              //[longitude addObject:lng];
              NSLog(@"%@%@%@",lat,lng,titles);
  
              if(lat == [NSNumber numberWithFloat:0.00]  &amp;&amp; lng == [NSNumber numberWithFloat:0.00])
              {
                  NSLog(@"%@%@%@",lat,lng,titles);
              }
              else
              {
                  CLLocationCoordinate2D coord;
                  coord.latitude =lat.doubleValue;
                  coord.longitude =lng.doubleValue;
                  MapViewAnnotation *annotation =[[MapViewAnnotation alloc]initWithTitle:titles AndCoordinate:coord];
                  [self.mapView addAnnotation:annotation];
              }
  </code></pre>
  
  <p>if condition is not satisfied because of NSNumber not check with null value.
  what is the way i can check?
  Tell me possible ways.. for checking null.</p>