#include  <math.h>
#include<dos.h>
#include<stdio.h>
#include  <graphics.h>
#include<conio.h>
void show(int i);
void erease(int i);

void main(void)
{
    int   driver = DETECT,mode;
    int   i;

    initgraph(&driver,&mode,"a:\\bgi");
  //  d:\\BC31\\bgi");

      setcolor(WHITE);
      line(1,400,400,400);
    for ( i = 0; i < 80; i++ )
     {  show(i);
	if (i>10) show(i-10);
	delay (300);
	erease(i);
	if (i>10) erease(i-10);
     }

    closegraph();
}
void show(int i)
{    int x, y;

    x=5*i;
    y=9*i-0.15*i*i;
    setcolor(RED);
    circle(400-x,400-y,2);
   // delay(300);
   // setcolor(BLACK);
   //circle(400-x,400-y,2);
}
void erease(int i)
{
   int x, y;
    x=5*i;
    y=9*i-0.15*i*i;
   setcolor(BLACK);
   circle(400-x,400-y,2);
}