Hex in C

point pointy_hex_corner(point center, float size, int i) {
    float angle_deg = 60 * i - 30;
    float angle_rad = (M_PI / 180.0) * angle_deg;
    return point{center.x + size * cos(angle_rad),
        center.y + size * sin(angle_rad)};
}

void drawPointyHex(point center, float hex_size) {
    point p0 = pointy_hex_corner(center, hex_size, 0);
    point p=p0;
    for (int i=1; i<6; ++i) {
        point np = pointy_hex_corner(center, hex_size, i);
        drawLine(p.x,p.y,np.x,np.y);
        p = np;
    }
    drawLine(p.x,p.y,p0.x,p0.y);
}