The comment was probably referring to things like "copying stuff is expensive" or "function calls are expensive", not more specific details of the machine you r

The comment was probably referring to things like "copying stuff is expensive" or "function calls are expensive", not more specific details of the machine you run on. In C++ you use pointers/references to solve the first problem, and define header-only classes for the latter. Even if you weren't aware, basic use of the the standard library will clue you in.