#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void main()
{
    int x=0,a,b;
    float r,d,y,d1,d2,l;
    int gd=DETECT,gm;
    initgraph(&gd,&gm," ");
    printf("Enter Radius");
    scanf("%f",&r);
    y=r;
    d=2*(1-r);
    l=0;
    while(y>=l)
    {
        putpixel(x,y,5);
        if(d<0)
        {
            d1=(2*d)+(2*y)-1;
            if(d1<=0)
            {
                x=x+1;
                d=d+(2*x)+1;
            }
            else
            {
                x=x+1;
                y=y-1;
                d=d+(2*x)-(2*y)+2;
            }
          }
        else if(d>0)
        {
            d2=(2*d)-(2*x)-1;
            if(d2<=0)
            {
                x=x+1;
                y=y-1;
                d=d+(2*x)-(2*y)+2;
            }
            else
            {
                y=y-1;
                d=d-(2*y)+1;
            }
        }
        else if(d==0)
        {
            x=x+1;
            y=y-1;
            d=d+(2*x)-(2*y)+2;
        }
    }
    getch();
}