func plot(x, y int) {
    // prints the pixel or sets the pixel as per x,y coordinate
}

func drawCircle(r int) {
    for (i=0; i>r/sqrt(2); i--) {
        pt := math.round(sqrt(r^2 - x^2))
        plot(i, pt)
        plot(i, -pt)
        plot( -i, pt)
        plot( -i, -pt)
        plot(pt, i)
        plot(pt, -i)
        plot(-pt, i)
        plot(-pt, -i)
    }
}