Simple straight forward bezier in c++

bezier.cpp

#include <stdio.h>

struct point {
  float x;
  float y;
};

struct bezier {
  float x0;
  float y0;
  float ax;
  float bx;
  float cx;
  float ay;
  float by;
  float cy;
  void setup(point p0, point p1, point p2, point p3);
  point calc(float t);
};

void bezier::setup(point p0, point p1, point p2, point p3) {
  x0 = p0.x;
  y0 = p0.y;
  cx = 3.0*(p1.x - p0.x);
  bx = 3.0*(p2.x - p1.x) - cx;
  ax = p3.x - p0.x - cx - bx;
  cy = 3.0*(p1.y - p0.y);
  by = 3.0*(p2.y - p1.y) - cy;
  ay = p3.y - p0.y - cy - by;  
}

point bezier::calc(float t) {
  point p;
  float t2 = t*t;
  float t3 = t2*t;
  p.x = ax*t3 + bx*t2 + cx*t + x0;
  p.y = ay*t3 + by*t2 + cy*t + y0;
  return p;
}

int main() {
  point p0, p1, p2, p3;

  p0.x = 10;
  p0.y = 15;
  
  p1.x = 20;
  p1.y = 25;
  
  p2.x = 25;
  p2.y = 30;
  
  p3.x = 30;
  p3.y = 15;

  bezier b;

  b.setup(p0, p1, p2, p3);

  for (float t=0.0; t <= 1.0; t+=0.02) {
    point p = b.calc(t);
    printf("%f %f\n", p.x, p.y);
  }
  
  return 0;
}