#include<stdio.h>
#include<graphics.h>
#include<math.h>
void main()
{
float p;
int i,gd,gm,x,y;
int r;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"\\tc\\bgi");
printf("Enter the radius of the circle :");
scanf("%d",&r);
x=0;
y=r;
p = 1.25 - r;
do
{
putpixel(200+x,200+y,15);
putpixel(200+y,200+x,15);
putpixel(200+x,200-y,15);
putpixel(200+y,200-x,15);
putpixel(200-x,200-y,15);
putpixel(200-x,200+y,15);
putpixel(200-y,200+x,15);
putpixel(200-y,200-x,15);
if (p < 0)
{
x = x+1;
y = y;
p = p + 2*x + 1;
}
else
{
x= x+1;
y= y-1;
p = p + 2*(x-y) + 1;
}
delay(100);
}
while(x < y);
getch();
closegraph();
}