Bresenham's algorithm to generate circle in third quadrant in anticlockwise direction

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

   int gd = DETECT, gm;
   int x1,y1=0,di,limit=0,R,d,d1,xi,yi;
   clrscr();

   initgraph(&gd, &gm,"C:\TC\BGI");
   xi=getmaxx()/2;
   yi=getmaxy()/2;
   setcolor(2);
   setbkcolor(8);

   printf("\n\n Enter the radius :");
   scanf("%d",&R);
   line(0,yi,xi*2,yi);
   line(xi,0,xi,yi*2);
   x1=-R;
   di=2*(1-R);
   putpixel(xi,yi,RED);
   while(x1<=limit)
     {
putpixel(xi+x1,yi-y1,RED);
delay(75);
if(di<0)
{
    d=(2*di)-(2*y1)-1;
    if(d<=0)
    {
         y1=y1-1;
         di=di-2*y1+1;
    }
    else
    {
         x1=x1+1;
        y1=y1-1;
        di=di+2*x1-2*y1+2;
    }
}
else
{
    if(di>0)
    {
       d1=2*di-2*x1-1;
       if(d1<=0)
       {
          x1=x1+1;
         y1=y1-1;
         di=di+2*x1-2*y1+2;
       }
       else
       {
    x1=x1+1;
    di=di+2*x1+1;
       }
    }
    else
    {
       if(di==0)
       {
    x1=x1+1;
          y1=y1-1;
          di=di+2*x1-2*y1+2;
       }
    }
}
     }
     getch();
     closegraph();
     }