Mine

        double along;
        along = 174.681821;
//      print_double("Score = %lf\n",along);

        double alat;
        alat = deg2rad(-36.788889);

        double blong;
        blong = 174.668494;
        double blat;
        blat = deg2rad(-36.788397);

        double adiff;
        adiff = blong - along;
        if (adiff > 180) {
                adiff -= 360;
        }
        if (adiff < -180) {
                adiff += 360;
        }

        double bdiff;
        bdiff = deg2rad(adiff);
        double cosdist;
        cosdist = (sin(alat) * sin(blat) + cos(alat) * cos(blat) * cos(bdiff));
        double rdist;
        rdist = acos(cosdist);

        double nautical_miles;
        nautical_miles = rad2deg(rdist) * 60;

        print_double("alat: %.15lf - blat: %.15lf - alat: %.15lf - blat: %.15lf - bdiff: %.15lf - cosdist: %.15lf - Distance: %.15lf\n", alat,blat,alat,blat,bdiff, cosdist, nautical_miles);