#include <cmath>

class sphere {
public:
    void assign_center( double x, double y, double z );
    double get_x_coord( void );
    double get_y_coord( void );
    double get_z_coord( void );
    void assign_radius( double r );
    double get_radius( void );
    double volume( void );
    sphere shifted_sphere ( double dx, double dy, double dz );
    void shift_sphere( double dx, double dy, double dz );
private:  // Only members functions can access private data
       double x_center, y_center, z_center, radius;
};

void sphere::assign_center( double x, double y, double z )
{
    x_center = x;
    y_center = y;
    z_center = z;
    return;
}

double sphere::get_x_coord( void )
{
    return( x_center );
}

double sphere::get_y_coord( void )
{
    return( y_center );
}

double sphere::get_z_coord( void )
{
    return( z_center );
}

void sphere::assign_radius( double r )
{
    radius = r;
    return;
}

double sphere::get_radius( void )
{
    return( radius );
}

double sphere::volume( void )
{
       double V = 4.0 * M_PI * pow( radius, 3 ) / 3.0;
       return( V );
}

sphere sphere::shifted_sphere( double dx, double dy, double dz )
{
    sphere new_sphere;
    // Since this function is a member function, it can access private data.
    new_sphere.x_center = x_center + dx;
    new_sphere.y_center = y_center + dy;
    new_sphere.z_center = z_center + dz;
    new_sphere.radius = radius;
    return( new_sphere );
}

void sphere::shift_sphere( double dx, double dy, double dz )
{
    x_center += dx;
    y_center += dy;
    z_center += dz;
    return;
}