#include <iostream.h>
#include <math.h>
#include "CPstring.h"
#include "list.h"
#include "place.h"
#include "distance.h"


static double DegToRad(double deg)
// pre: deg = degrees measure
// post: returns # radians = deg
{
    return deg * 3.14159/180;
}

double Distance::ComputeDistance
(double lat1, double long1, double lat2, double long2)
// postcondition: returns miles between a (lat1, long1)
//                and b (lat2, long2).
//                (a/b are latitude/longitude)
{
    const double RADIUS = 6366*0.62;  // Earth's radius in miles
    const double UNITS_TO_DEGREES = 1000000.;

    // transform from database units to degrees
    long1 /= UNITS_TO_DEGREES;
    lat1  /= UNITS_TO_DEGREES;
    long2 /= UNITS_TO_DEGREES;
    lat2  /= UNITS_TO_DEGREES;
    
    return RADIUS * acos(sin(DegToRad(lat1)) *
                         sin(DegToRad(lat2)) +
                         (cos(DegToRad(lat1)) *
                          cos(DegToRad(lat2)) *
                          cos(DegToRad(long1-long2)))
                         );
    
}


Distance::Distance()  // constructor
{
    // nothing to construct, no private data
}

Distance::~Distance()
{
    // Do Nothing
}

void Distance::Function(string & name, List<Place> &list)
{
    // please implement me
}

void Distance::Report()
{
    cout << "nothing to report from class Distance" << endl;
}