Движение прямоугольника

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <graphics.h>
#include <dos.h>
class gr_init
{
public:
gr_init(int driver = 0)
{
*gd = driver;
initgraph(gd, gm, "");
if(graphresult() != 0) {printf("Error!"); abort();}
}
~gr_init()
{
closegraph();
}
private:
int *gd, *gm;
};
 
class gr_obj
{
public:
gr_obj(int col = 7)
{_color = col;}
virtual void draw() = 0;
int color()
{
return _color;
}
public:
void show()
{
setcolor(color()); draw();
}
void hide()
{
cback = getcolor(); setcolor(getbkcolor()); draw(); setcolor(color());
}
private:
int _color, cback;
};
 
class point: public gr_obj
{
public:
point(int xp = 0, int yp = 0, int col = 7): gr_obj(col)
{setpx(xp); setpy(yp); show();}
~point()
{
hide();
}
void draw()
{
putpixel(x, y, color());
}
int getpx()
{
return x;
}
void setpx(int px)
{
x = px;
}
int getpy()
{
return y;
}
void setpy(int py)
{
y = py;
}
private:
int x, y;
};
class pryam: public point
{
public:
pryam(int xc = 0, int yc = 0, int pa = 0, int col = 7): point(xc, yc, col)
{a = pa; show(); }
~pryam()
{
hide();
}
void draw()
{
rectangle(getpx(),getpy(),getpx1(), getpy1());
}
int getpx1()
{
return x1;
}
void setpx1(int px)
{
x1 = px;
}
int getpy1()
{
return y1;
}
void setpy1(int py)
{
y1 = py;
}
void move(int newx, int newy, int newx1, int newy1)
{
hide();
setpx(newx); setpy(newy);
setpx1(newx1); setpy1(newy1);
show();
}
private:
int x1, y1, a;
};
 
void main()
{
gr_init gr(0);
pryam pr(300-50, 300-50, 300+50, 300+50);
for(int i = 1; i < 57; i++)
{
pr.move(100-100+i*2,100-100+i*2,100+100+i*2,100+100+i*2); delay(200);
}
getch();
}

pr.move(100-100+i*2,100-100,100+100+i*2,100+100);