How to compare user'r current location to other locations and display them in UITable View?

Question

I am developing an app in swift and I have to compare user's current location to the other locations taken from a JSON file. Then I have to display all of the locations which are in a certain range from the user's location. This range I take from a UISlider. I mean when the user selects 25km in the slider, the app has to determine the current user's location and display all of the fruits which are in this range.

   import UIKit
   import SwiftyJSON
   import MapKit
   import CoreLocation


 class TableViewController: UITableViewController,CLLocationManagerDelegate {
 @IBOutlet weak var Bar: UIToolbar!


@IBOutlet weak var LabelTest: UILabel! // this is the slider value, I segue it from the previous viewcontroller
var manager = CLLocationManager()

struct Fruit {
    let name : String
    let location : CLLocation
    let imageURL : NSURL
    let description : String
}
var fruits = [Fruit]()


func parseFruits() {
    guard let url = NSBundle.mainBundle().URLForResource("cities", withExtension: "json"), jsonData = NSData(contentsOfURL: url) else {
        print("Error finding JSON File")
        return
    }

    let jsonObject = JSON(data: jsonData)

    let fruitArray = jsonObject["fruits"].arrayValue
    for aFruit in fruitArray {
       let name = aFruit["Name"].stringValue
        let latitude = city["Latitude"] as! Double
        let longitude = city["Longitude"] as! Double
        let location = CLLocation(latitude: latitude, longitude: longitude)
       let imageURL = aFruit["Picture"].stringValue
    let description = aFruit["Description"].stringValue

        let fruit = Fruit(name: name,location: location,imageURL: NSURL(string:imageURL)!, description: description )
        fruits.append(fruit)
    }

    self.tableView.reloadData()
}

override func viewDidLoad() {
    super.viewDidLoad()
    parseFruits()

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem()
}

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

// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return fruits.count
    }



override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
     let cell: TableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell") as!  TableViewCell
     let fruit = fruits[indexPath.row]
    cell.CellTitle.text = fruit.name
    cell.CellDescription.text = fruit.description


    let image = UIImage(data: NSData(contentsOfURL:(string: fruit.imageURL))!)
    cell.CellImage.image = image

    return cell
          }

Currently I am not calculating the user's current location and I am not comparing it, I would be glad if someone can show me how to do that.

edited:

   func CalculateDistance() {
    let userLocation = CLLocation(latitude: lat, longitude: long)
    let destinationLocation = CLLocation(latitude:latitude, longitude: longitude)// latitude and longitude from the json file
    let distance = userLocation.distanceFromLocation(destinationLocation)
}

Answer 1

When you want to calculate the distance between two locations you can do the following:

let userLocation = CLLocation(latitude: lat, longitude: long)
let destinationLocation = CLLocation(latitude: (dest.lat as NSString).doubleValue, longitude: (dest.long as NSString).doubleValue)
let distance = userLocation.distanceFromLocation(destinationLocation)

Get the userLocation which is the current location of the user. Then you have the location of the destination and then calculate the distance with the help of the distanceFromLocation function which is a part of CoreLocation.

Then I have done a method that rounds the distance to nearest 5 meters:

var distanceToFive = roundToFive(distance)

private func roundToFive(x : Double) -> Int {
    return 5 * Int(round(x / 5.0))
}

You can of course change this to 10, 20 etc.

Edit:
And to get the current location:
Add the CLLocationManagerDelegate to the class inheritance. Declare var locationManager = CLLocationManager() and two variables one for lat and one for long. In viewDidLoad do

self.locationManager.requestWhenInUseAuthorization()
    if CLLocationManager.locationServicesEnabled() {
        locationManager.delegate = self
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
    }

And then to get the location for the user declare the following methods:

func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        let location:CLLocationCoordinate2D = manager.location!.coordinate
        lat = location.latitude
        long = location.longitude
    }

    func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
        print("Error")
    }

Edit2:

func CalculateDistance() -> Int{
    let userLocation = CLLocation(latitude: lat, longitude: long)
    let destinationLocation = CLLocation(latitude:latitude, longitude: longitude)// latitude and longitude from the json file
    let distance = userLocation.distanceFromLocation(destinationLocation)

    return roundToFive(distance)
}

private func roundToFive(x : Double) -> Int {
    return 5 * Int(round(x / 5.0))
}