For page 33: " struct Circle { const struct Point _; int rad; }; We let the derived structure start with a copy of the base structure that we are extending

For page 33: " struct Circle { const struct Point _; int rad; }; We let the derived structure start with a copy of the base structure that we are extending. Information hiding demands that we should never reach into the base structure directly; therefore, we use an almost invisible underscore as its name and we declare it to be constto ward off careless assignments. " This looks so manual that reminds me "C with classes". It is a very pedagogic read though.