bresenham algorithm for circle code example

Example 1: bresenham circle drawing algorithm

void    EightWaySymmetricPlot(int xc,int yc,int x,int y)  
   {  
    putpixel(x+xc,y+yc,RED);  
    putpixel(x+xc,-y+yc,YELLOW);  
    putpixel(-x+xc,-y+yc,GREEN);  
    putpixel(-x+xc,y+yc,YELLOW);  
    putpixel(y+xc,x+yc,12);  
    putpixel(y+xc,-x+yc,14);  
    putpixel(-y+xc,-x+yc,15);  
    putpixel(-y+xc,x+yc,6);  
   }  
  
    void BresenhamCircle(int xc,int yc,int r)  
   {  
    int x=0,y=r,d=3-(2*r);  
    EightWaySymmetricPlot(xc,yc,x,y);  
  
    while(x<=y)  
     {  
      if(d<=0)  
             {  
        d=d+(4*x)+6;  
      }  
     else  
      {  
        d=d+(4*x)-(4*y)+10;  
        y=y-1;  
      }  
       x=x+1;  
       EightWaySymmetricPlot(xc,yc,x,y);  
      }  
    }

Example 2: bresenham algorithm

function line(x0, y0, x1, y1) {
   var dx = Math.abs(x1 - x0);
   var dy = Math.abs(y1 - y0);
   var sx = (x0 < x1) ? 1 : -1;
   var sy = (y0 < y1) ? 1 : -1;
   var err = dx - dy;

   while(true) {
      setPixel(x0, y0); // Do what you need to for this

      if ((x0 === x1) && (y0 === y1)) break;
      var e2 = 2*err;
      if (e2 > -dy) { err -= dy; x0  += sx; }
      if (e2 < dx) { err += dx; y0  += sy; }
   }
}