Arie Triunghi

int arie(int x1, int y1, int x2, int y2, int x3, int y3) {
  int area;
  area = (x3 - x1) * (y2 - y1) - (x2 - x1) * (y3 - y1);
  if(area < 0)
    area *= -1;
  return area;
}