I want to calculate the sum in the array.

import UIKit
import CoreMotion

classViewController:UIViewController {

@IBOutlet weak var Myaccelx: UILabel!
@IBOutlet weak var accelxaddition: UILabel!


let motionManager: CMMotionManager= CMMotionManager()
vartimer —NSTimer=NSTimer()
var countArray=[String]( ) // Array
var bele = 20
varkazu = 0
varj = 0
var num = 0


override func viewDidLoad(){
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from anib.

    // Initialize MotionManager
    motionManager.deviceMotionUpdateInterval=0.05//20Hz

    // Start motion data acquisition
    motionManager.startDeviceMotionUpdatesToQueue(NSOperationQueue.currentQueue(), withHandler: {
        deviceManager, error in
        varaccel:CMACceleration=deviceManager.userAcceleration

        self.countArray.append("\(accel.x)")

        if self.countArray.count>=self.bele{
            self.countArray.removeAtIndex(0)
        }

        self.Myaccelx.text=("\(self.countArray)")

        self.timer = NSTimer.scheduledTimerWithTimeInterval (1, target:self, selector: "Count", userInfo:nil, repeat:true)
    })
}


func Count() {



}

override funcdidReceiveMemoryWarning(){
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
 }


}