A program that calculates the distance a hot air ballon has to travel to circumnavigate the globe.

program.cpp

/**
 * A short program to calculate the approximate length of a journey around the
 * globe in a hot air balloon.
 * 
 * Authored by Philip Castiglione
 */
#include "splashkit.h"

using namespace std;

#define PI 3.14159           // PI to 5 decimal places
#define FEET_CMS 30.48       // centimeters in a foot
#define RADIUS_OF_EARTH 6371 // radius of earth in kilometers

/**
 * Convert a distance in feet to kilometers.
 *
 * @params distance    The distance in feet
 */
void convert_feet_to_kms(double &distance)
{
    distance *= FEET_CMS; // convert distance from feet to cms
    distance /= 100;      // convert distance from cms to meters
    distance /= 1000;     // convert distance from meters to kms
}

/**
 * Calculate a circumference given a radius.
 * 
 * @param   radius          The radius of a cirle (or sphere)
 * @returns circumference   The circumference of the circle
 */
double calculate_circumference(double radius)
{
    return 2 * PI * radius;
}

/**
 * Calculate the distance around the earth in a hot air balloon.
 * 
 * @returns distance    The distance around the earth in the balloon
 */
double calculate_distance()
{
    double altitude, total_radius, distance;
    
    altitude = 2000.0; // altitude of the balloon in feet
    convert_feet_to_kms(altitude);

    total_radius = RADIUS_OF_EARTH + altitude;
    distance = calculate_circumference(total_radius);

    return distance;
}

int main()
{
    double total_distance;

    total_distance = calculate_distance();

    write_line("The total distance travelled in kms will be: " +
               to_string(total_distance));

    return 0;
}