问在速度计应用程序中保持最大速度

EN

func locationManager(manager:CLLocationManager, didUpdateLocations locations:[CLLocation]) {
        var latestLocation = locations.last as CLLocation!
        var maxSpeed: Double = 0

        latLabel.text = "\(latestLocation.coordinate.latitude)"
        lonLabel.text = "\(latestLocation.coordinate.longitude)"

        var speed: CLLocationSpeed = CLLocationSpeed()
        speed = locationManager.location!.speed
        if(speed<0){
            speed=0;
        }
        speedLabel.text = String(format: "%.0f km/h", speed * 3.6)

        maxSpeed = max(maxSpeed, speed)

        maxSpeedLabel.text = String(format: "%.0f km/h", maxSpeed*3.6)
    }