Не рисуются линии

#include<iostream.h>
#include<graphics.h>
#include<conio.h>
 
struct Point
{
int x,y;
};
class Line
{
Point p1,p2;
long A,B,C;
  public:
  //
  void setLine(Point pp1,Point pp2)
    {
    p1=pp1; p2=pp2;
    A=(long)p2.y-p1.y;
    B=(long)p1.x-p2.x;
    C=(long)p1.y*(p2.x-p1.x)-(long)p1.x*(p2.y-p1.y);
    }
  Point getP1() {return p1;}
  Point getP2() {return p2;}
 
       int checkSign(Point p)
       {
       long eq=A*p.x+B*p.y+C;
       if (eq>0) return 1;
       if (eq==0) return 0; return -1;
       }
       int checkCrossed(Line l)
       {
       if (checkSign(l.p1)*checkSign(l.p2)>0) return 0; return 1;
       }
       void draw() {line (p1.x, p1.y, p2.x, p2.y);}
 
};
 
int main()
{
 int gdriver = DETECT, gmode, errorcode;
 initgraph(&gdriver, &gmode, "d:\\BC\\BGI");
 errorcode = graphresult();
 if (errorcode !=grOk)
   {
   cout<<"Graphics error:\n"<<grapherrormsg(errorcode);
   return 1;
   }
 Point p1,p2,p3,p4;
 p1.x=100; p1.y=100; p2.x=300; p2.y=300;
 p3.x=200; p3.y=202; p4.x=200; p4.y=400;
 Line l1,l2;
 l1.setLine(p1,p2);
 l2.setLine(p3,p4);
 if (l1.checkCrossed(l2)&&l2.checkCrossed(l1))
 setcolor(RED);
 else setcolor(GREEN);
 l1.draw();
 l2.draw();
 getch();
 closegraph();
 return 0;
}