I am receiving multiple restaurants' latitude/longitude from a server. I want to calculate the d开发者_StackOverflow中文版istance between each restaurant and the user's current latitude/longitude.

You can use distanceFromLocation: method of CLLocation which returns the distance in meters between two CLLocation's.

CLLocation *currentLoc = /* Assume you have found it */;
CLLocation *restaurantLoc = [[CLLocation alloc] initWithLatitude:restaurantLat longitude:restaurantLng];
CLLocationDistance meters = [restaurantLoc distanceFromLocation:currentLoc];
// Go ahead with this

Once you have a list of places (one way or the other) you can the get the distance to (or from) these using CoreLocation to calculate this with distanceFromLocation:

You can use an API provided by Google for the same. The Google Distance Matrix API

Its perfect for finding distance. Hope it helps.

Swift 3

func calculateDistanceFromUser(location:CLLocation)->CLLocation!{
    if let userLocation = self.userUpdatedLocation{ //CLLocation
        let meters = location.distance(from: userLocation)
        return meters
    }
    return nil
}