#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <graphics.h>
void main() {
int    GraphDriver;             /* The Graphics device driver           */
int    GraphMode;               /* The Graphics mode value              */
struct point { int x,y; } p1,p2;
int radius;
float x,y,t,i;

  printf("give me the circle point--->"); scanf("%d %d",&p1.x,&p1.y);
  printf("give me the radius --->"); scanf("%d",&radius);
  getche();

  GraphDriver = DETECT;                 /* Request auto-detection       */
  initgraph( &GraphDriver, &GraphMode, "" ); /* just increasing p1 - p2 */

  setcolor(14); circle(p1.x,p1.y,radius); getche(); clearviewport();

  for (i=p1.x-radius; i<=p1.x+radius; i+=0.5) {
    t=sqrt(radius*radius-(i-p1.x)*(i-p1.x));
    y=p1.y+t; putpixel(i,(int)y,2);
    y=p1.y-t; putpixel(i,(int)y,3); delay(20);
  }
  getche();
  closegraph();                 /* Return the system to text mode       */
}