Bresenhams Circle Drawing ALgorithm

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void main()
{

int r,x,y,d,gd,gm;
detectgraph(&gd,&gm);
initgraph(&gd,&gm,"C:\TC\BIN");


printf("enter the radius of circle");
scanf("%d",&r);
d=3-(2*r);  // initialising decision variable
x=0;
y=r;
do
 {
   putpixel(200+x,200+y,15);
   putpixel(200+y,200+x,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);
  putpixel(200-x,200+y,15);
    if(d<0)
    {
      d=d+(4*x)+6;
    }
     else
      {
       d=d+4*(x-y)+10;
       y=y-1;
      }
      x=x+1;
    }
    while(x<y);
    getch();
    closegraph();

    }