title: initialize CLCircularRegion in Swift
body: <p>I am fairly new to programming for iOS and am teaching myself how to use Swift. I need to set up geofencing for an app I am making for a class. My problem is when initializing CLCircularRegion I get an error that says "<strong>Use of undeclared type 'center'</strong>". I followed the documents from Apple's developer site and have no clue what I am doing wrong. Any help would be greatly appreciated. Thank you.</p>
  
  <pre><code>import UIKit
  import MapKit
  import CoreLocation
  
  class ViewController: UIViewController, MKMapViewDelegate, CLLocationManagerDelegate {
  
  @IBOutlet var mapView: MKMapView!
  
  var manager = CLLocationManager()
  
  @IBAction func startMonitoring(sender: AnyObject) {
      // 43.039278, -87.932479 mccormick hall location
      var latitude:CLLocationDegrees = 43.039278
      var longitude:CLLocationDegrees = -87.932479
      var center:CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
      var radius:CLLocationDistance = CLLocationDistance(10.0)
      var identifier:String = "vicmic"
  
      var geoRegion:CLCircularRegion = CLCircularRegion(center: center, radius: radius, identifier: identifier)
  
  }
  
  
  override func viewDidLoad() {
      super.viewDidLoad()
  
      // Core Location
      manager.delegate = self
      manager.desiredAccuracy = kCLLocationAccuracyBest
      manager.requestWhenInUseAuthorization()
      manager.startUpdatingLocation()
  
  }
  
  override func didReceiveMemoryWarning() {
      super.didReceiveMemoryWarning()
      // Dispose of any resources that can be recreated.
  }
  
  
  }
  </code></pre>