Создать функцию, тестирующую вхождение точки в шар

#include <iostream>
#include <cmath>
using std::cin;
using std::cout;
 
typedef struct _TPoint 
{   double x,y,z;
}   TPoint;
 
typedef struct _TSphere
{   TPoint *center;
    double radius;
}   TSphere;
 
double Distance (TPoint *p1, TPoint *p2)
{   return sqrt((p1->x - p2->x)*(p1->x - p2->x) + (p1->y - p2->y)*(p1->y - p2->y) + (p1->z - p2->z)*(p1->z - p2->z));
}
 
bool IsInSphere (TSphere *sphere, TPoint *point)
{   return Distance (point, sphere->center) < sphere->radius;
}
 
TSphere *CreateSphere (TPoint *_center, double _radius)
{   TSphere *sphere = new TSphere;
    sphere->center = new TPoint;
    sphere->center->x = _center->x;
    sphere->center->y = _center->y;
    sphere->center->z = _center->z;
    sphere->radius = _radius;
    return sphere;
}
 
void DeleteSphere (TSphere *sphere)
{   delete sphere->center;
    delete sphere;
}
 
int main()
{   TPoint p;
    double r;
    
    cout << "Set sphere:\n";
    cout << "\tradius:\t";
    cin >> r;
    cout << "\tcenter: x, y, z :\t";
    cin >> p.x >> p.y >> p.z;
    TSphere *s = CreateSphere (&p, r);
 
    cout << "Set point:\n";
    cout << "\tx, y, z :\t";
    cin >> p.x >> p.y >> p.z;
 
    if (IsInSphere (s, &p))
        cout << "\n\nPoint WITHIN sphere";
    else
        cout << "\n\nPoint BEYOND sphere";
 
    DeleteSphere (s);
    cin.sync(); cin.get();
    return 0;
}