//  PlacesOnEarth.java  (c) 2005 Kari Laitinen

//  http://www.naturalprogramming.com

//  2005-05-04  File created.
//  2005-05-05  Last modification.

//  This program demonstrates the use of some Math methods.

//  Class PlaceOnEarth presented in this program is a lightweight
//  version of the Place_on_earth class which is presented in
//  the programs of my C++ book.

import java.util.* ;

class  PlaceOnEarth
{
   String  place_name ;
   String  country_name ;

   int     degrees_of_latitude ;
   int     minutes_of_latitude ;
   int     degrees_of_longitude ;
   int     minutes_of_longitude ;

   public PlaceOnEarth( String given_place_name,
                        String given_country_name,
                        int   given_degrees_latitude,
                        int   given_minutes_latitude,
                        int   given_degrees_longitude,
                        int   given_minutes_longitude )
   {
      place_name            =  given_place_name ;
      country_name          =  given_country_name ;
      degrees_of_latitude   =  given_degrees_latitude ;
      minutes_of_latitude   =  given_minutes_latitude ;
      degrees_of_longitude  =  given_degrees_longitude ;
      minutes_of_longitude  =  given_minutes_longitude ;
   }

   public String  get_place_name()    { return place_name ; }
   public String  get_country_name()  { return country_name ; }

   public long get_distance_to( PlaceOnEarth another_place )
   {

      long distance_to_caller  = 
   
         calculate_distance_on_earth_surface(
      
                                   degrees_of_latitude,
                                   minutes_of_latitude,
                                   degrees_of_longitude,
                                   minutes_of_longitude,
                                   another_place.degrees_of_latitude,
                                   another_place.minutes_of_latitude,
                                   another_place.degrees_of_longitude,
                                   another_place.minutes_of_longitude ) ;
      
      return  distance_to_caller ;
   }

   static final double  EARTH_RADIUS_IN_KILOMETERS  =  6370  ;
 
   public static long
   calculate_distance_on_earth_surface( double  point_1_latitude,
                                        double  point_1_longitude,
                                        double  point_2_latitude,
                                        double  point_2_longitude )
   {
      //  All latitudes and longitudes must be expressed
      //  in radians when calling this method.
   
      double cosine_of_angle_between_points  =
   
                     Math.cos( point_1_latitude ) *
                     Math.cos( point_2_latitude ) *
                     Math.cos( point_1_longitude - point_2_longitude )
   
                     +
   
                     Math.sin( point_1_latitude ) *
                     Math.sin( point_2_latitude )   ;
   
      double angle_between_points  =
                     Math.acos( cosine_of_angle_between_points ) ;
   
      long distance_to_caller  =  (long) ( angle_between_points *
                                           EARTH_RADIUS_IN_KILOMETERS ) ;

      return  distance_to_caller ;
   }

   //  The following function takes arguments as degrees and minutes,
   //  converts them to radians, and then calls the function above.
   
   public static long
   calculate_distance_on_earth_surface( int  point_1_latitude_degrees,
                                        int  point_1_latitude_minutes,
                                        int  point_1_longitude_degrees,
                                        int  point_1_longitude_minutes,
                                        int  point_2_latitude_degrees,
                                        int  point_2_latitude_minutes,
                                        int  point_2_longitude_degrees,
                                        int  point_2_longitude_minutes )
   {
      return
   
         calculate_distance_on_earth_surface(
      
               Math.toRadians( (double) point_1_latitude_degrees  +
                               (double) point_1_latitude_minutes  / 60.0 ),
               Math.toRadians( (double) point_1_longitude_degrees +
                               (double) point_1_longitude_minutes / 60.0 ),
               Math.toRadians( (double) point_2_latitude_degrees  +
                               (double) point_2_latitude_minutes  / 60.0 ),
               Math.toRadians( (double) point_2_longitude_degrees +
                               (double) point_2_longitude_minutes / 60.0 ) ) ;
   }


}

class PlacesOnEarth
{
   public static void main( String[] not_in_use )
   {
      Scanner  keyboard  =  new Scanner( System.in ) ;

      PlaceOnEarth  new_york_in_usa  =  new  PlaceOnEarth( "New York",
                                                           "New York USA",
                                                          40, 45, -74, 00  ) ;
      PlaceOnEarth  tokyo_in_japan  =  new  PlaceOnEarth( "Tokyo",
                                                          "Japan",
                                                           35, 45, 139, 45 ) ;

      System.out.print( "\n Distance is "
                     +  new_york_in_usa.get_distance_to( tokyo_in_japan ) 
                     +  "\n\n"  ) ;
   }
}