Apex method to check distance between to lon/lat points

distance-between-lon-lat.cls

List<Account> listOfAccounts = [ SELECT Id, Name, ShippingLongitude, ShippingLatitude FROM Account WHERE ShippingLatitude != NULL];

Location userLocation = Location.newInstance(-35.4330529, 149.0699176);

System.debug('a userLocation ' + userLocation);
for (Account account : listOfAccounts) {
    Location placeLocation = Location.newInstance(account.ShippingLatitude, account.ShippingLongitude);
    Double distanceBetween = Location.getDistance(userLocation, placeLocation, 'km');
    System.debug('Distance Between ' + distanceBetween + 'km');
}