Bresenham's Circle Drawing algo

# include<stdio.h>
# include<conio.h>
# include<graphics.h>
# include<math.h>
# include<dos.h>

void main()
{
int gd=DETECT,gm;
int r,x,y,p,xc,yc;

initgraph(&gd,&gm,"C:\\TC\\BGI");
cleardevice();


printf("Enter the radius ");
scanf("%d",&r);
printf("\n Enter the centre of circle");
scanf("%d%d",&xc,&yc);
line(320,0,320,480);
line(0,240,640,240);

x=0;
y=r;
putpixel(xc+x,yc-y,1);

p=3-(2*r);

for(x=0;x<=y;x++)
{
if (p<0)
{
y=y;
p=(p+(4*x)+6);
}
else
{
y=y-1;

p=p+((4*(x-y)+10));
}

putpixel(320+xc+x,240-yc-y,1);
putpixel(320+xc-x,240-yc-y,2);
putpixel(320+xc+x,240-yc+y,3);
putpixel(320+xc-x,240-yc+y,4);
putpixel(320+xc+y,240-yc-x,5);
putpixel(320+xc-y,240-yc-x,6);
putpixel(320+xc+y,240-yc+x,7);
putpixel(320+xc-y,240-yc+x,8);
sleep(1);

}
getch();
closegraph();
}