Show HN: Pi Approximation using Monte Carlo(montepie.herokuapp.com)

    float residual = x*x + y*y - 1
    if (residual == 0) {
        /* x*x + y*y rounded to 1; we need to do a more careful check
           to determine whether we're inside or outside.  WLOG, assume
           that |x| >= |y|. */
        if (fabsf(x) < fabsf(y)) { float tmp = x; x = y; y = tmp; }
        /* We know that 0.5 <= x*x < 1.0, from which it follows that
           fmaf(x,x,-1) is computed without any rounding; we can then
           do another fma to isolate the residual (this is also exact
           because we know that y*y cannot be *too* tiny unless x is
           exactly 1.0, in which case the first fma is exactly zero). */
        residual = fmaf(y,y,fmaf(x,x,-1));
    }
    if (residual < 0) { /* inside circle */ }
    else if (residual == 0) { /* on circle */ }
    else { /* outside circle */ }