#include<stdio.h>
#include<math.h>
#include<graphics.h>
yuan(xc,yc,radius,c)
int xc,yc,radius,c;
{
int x,y,p;
x=0;
y=radius;
p=3-2*radius;
while(x<y){
plot_circle_points(xc,yc,x,y,c);
if(p<0) p=p+4*x+6;
else{
p=p+4*(x-y)+10;
y-=1;
}x+=1;
}
if(x==y)
plot_circle_points(xc,yc,x,y,c);
}

plot_circle_points(xc,yc,x,y,c)
int xc,yc,x,y,c;
{putpixel(xc+x,yc+y,c);
 putpixel(xc-x,yc+y,c);
 putpixel(xc+x,yc-y,c);
 putpixel(xc-x,yc-y,c);
 putpixel(xc+y,yc+x,c);
 putpixel(xc-y,yc+x,c);
 putpixel(xc+y,yc-x,c);
 putpixel(xc-y,yc-x,c);
}
main()
{int xc,yc,x,y,c,radius;
int gdriver=DETECT,gmode;
printf("Input the xc,yc:");
scanf("%d,%d",&xc,&yc);
printf("Input the radius,c:");
scanf("%d,%d",&radius,&c);
initgraph(&gdriver,&gmode,"d:\\tc20");
cleardevice();
yuan(xc,yc,radius,c);
getch();
closegraph();
}