Superellipse Stroustrup - c++

Question

Exercise 13, from Chapter 12 of Stroustrup's Programming principles and practice using c++.
A superellipse is a two-dimensional shape defined by the equation
Look up superellipse on the web to get a better idea of what such
shapes look like. Write a program that draws "starlike" patterns by
connecting points on a superellipse. Take a, b, m, n, and N as
arguments.
Select N points on the superellipse defined by a, b, m,
and n. Make the points equally spaced for some definition of
"equal" Connect each of those N points to one or more other points
(if you like you can make the number of points connected to another
argument or just use N-1, i.e., all me orner points).
i have a vector that contains points with which i can build the superellipse
i cant get the second part of exercise - how to find N-points lying on superellipse to build stars?
thanks
//------------------------------------------------------------------------------
struct Point {
int x, y;
Point(int xx, int yy) : x(xx), y(yy) { }
Point() :x(0), y(0) { }
};
//------------------------------------------------------------------------------
int sgn(double d) {
if (d < 0)
return -1;
if (d == 0)
return 0;
if (d > 0)
return 1;
// exception
error("sgn: something gone wrong\n");
}
//------------------------------------------------------------------------------
vector<Point> superellipse(double a, double b, double m, double n, double precision = 0.01, int xCenter = 200, int yCenter = 200) {
if (precision >= 1.00 || precision < 0.001)
error ("use numbers from range [0.001 ; 1.00) for precision parametr\n");
vector<Point> points;
Point temp;
Point P;
for (double d = -1.0; d < 1.00; d += precision) {
double t = d*M_PI;
int x = pow((abs(cos(t))),2.0/m) * a * sgn(cos(t));
int y = pow((abs(sin(t))),2.0/n) * b * sgn(sin(t));
P = Point(x + xCenter, y + yCenter);
if (P != temp) // ignore dublicates
points.push_back(P);
temp = P;
}
return points;
}
//------------------------------------------------------------------------------

Answer 1

1.scratch
vector<Point> superellipse (/*...*/) {
/* */
return points;
}
2.put
class Superellipse {
std::vector<Point> _points;
void draw_connected(const Point& A, const Point& B);
public:
void draw_star(/* params */);
Superellipse(/* params*/){
/* initialize _points*/
}
};
i cant get the second part of exercise - how to find N-points lying on
superellipse to build stars?
???
You already have the points in your vector.
http://www.stroustrup.com/Programming/programming_ch12.pdf
if you like you can make the number of points connect to another
argument or just use N–1, i.e., all the other points
void Superellipse::draw_star (/* */){
int N = _points.size();
for (int i = 0; i < N; ++i) {
for (int j = i + 1; j < N; ++j) {
draw_connected (_points[i], _points[j]);
}
}
}