using System;

​

public class Program

{

    public static double ConvertToFeet(double miles)

    {

        return (miles * 5280);

    }

​

    public static void Main()

    {

        Position qnxtPos = new Position();

        qnxtPos.Latitude = Convert.ToDouble(26.081136);

        qnxtPos.Longitude = Convert.ToDouble(-80.250788);

        Position facetsPos = new Position();

        facetsPos.Latitude = Convert.ToDouble(26.081674);

        facetsPos.Longitude = Convert.ToDouble(-80.249866);

        Haversine calc = new Haversine();

        double result = calc.Distance(qnxtPos, facetsPos, DistanceType.Miles);

        Console.WriteLine(ConvertToFeet(result));

    }

}

​

public enum DistanceType

{

    Miles,

    Kilometers

}

​

;

public struct Position

{

    public double Latitude;

    public double Longitude;

}

​

class Haversine

{

    public double Distance(Position pos1, Position pos2, DistanceType type)

    {

        double preDlat = pos2.Latitude - pos1.Latitude;

        double preDlon = pos2.Longitude - pos1.Longitude;

        double R = (type == DistanceType.Miles) ? 3960 : 6371;

        double dLat = this.ToRadian(preDlat);

        double dLon = this.ToRadian(preDlon);

        double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) + Math.Cos(this.ToRadian(pos1.Latitude)) * Math.Cos(this.ToRadian(pos2.Latitude)) * Math.Sin(dLon / 2) * Math.Sin(dLon / 2);

        double c = 2 * Math.Asin(Math.Min(1, Math.Sqrt(a)));

        double d = R * c;

        return d;

    }

​

    private double ToRadian(double val)

    {

        return (Math.PI / 180) * val;

    }

}