This is from chapter 13. Create a class that draws a box with rounded corners. I got the math figured out, but for some reason the lines are not being drawn to the screen. What could be the problem?

Code:struct Box:Shape { Box(Point xxyy, int ww, int hh); void Top_segment(); void Bottom_segment(); void Left_side_segment(); void Right_side_segment(); void draw_lines() const; int height() const { return h; } int width() const { return w; } private: Point xy; //left most corner Lines cornerless_box; // create a box with no corners using line segments int h; // height int w; // width double width_tenth; //10% of the width that will calculate the length to remove from each side to make room for the arcs }; //---------------------------------------------------------------- //---------------------------------------------------------------- //---------------------------------------------------------------- Box::Box(Point xxyy, int ww, int hh):w(ww), h(hh), xy(xxyy) { width_tenth = (xy.x + w) * 0.10; if (h <= 0 || w <= 0) error("Bad rectangle: non-positive side"); } //---------------------------------------------------------------- void Box::Top_segment() { double top_seg_begin_w; //where the line segment will begin after deducting 10% of w; double top_seg_end_w; //where the line segment will end after deducting 10% of w; top_seg_begin_w = xy.x + width_tenth; top_seg_end_w = (xy.x + w) - width_tenth; double top_seg_y = xy.y; cornerless_box.add(Point(top_seg_begin_w, top_seg_y), Point(top_seg_end_w, top_seg_y)); } //---------------------------------------------------------------- void Box::Bottom_segment() { double bottom_seg_begin_w; double bottom_seg_end_w; bottom_seg_begin_w = xy.x + width_tenth; bottom_seg_end_w = (xy.x + w) - width_tenth; double y_bottom = xy.y + h; cornerless_box.add(Point(bottom_seg_begin_w, y_bottom), Point(bottom_seg_end_w, y_bottom)); } //---------------------------------------------------------------- //---------------------------------------------------------------- void Box::Left_side_segment() { double left_seg_begin_h; double left_seg_end_h; left_seg_begin_h = xy.y + width_tenth; left_seg_end_h = (xy.y + h) - width_tenth; double x_left = xy.x; cornerless_box.add(Point(x_left, left_seg_begin_h), Point(x_left, left_seg_end_h)); } //---------------------------------------------------------------- void Box::Right_side_segment() { double right_seg_begin_h; double right_seg_end_h; right_seg_begin_h = xy.y + width_tenth; right_seg_end_h = (xy.y + h) - width_tenth; double x_right = xy.x + w; cornerless_box.add(Point(x_right, right_seg_begin_h), Point(x_right, right_seg_end_h)); }