size of pointers and architecture

Question

By conducting a basic test by running a simple C++ program on a normal desktop PC it seems plausible to suppose that sizes of pointers of any type (including pointers to fun

Answer 1

For correctness, you cannot assume anything. You have to check and be prepared to deal with weird situations.

As a general rule of thumb, it is a reasonable default assumption.

It's not universally true though. See the X32 ABI, for example, which uses 32bit pointers on 64bit architectures to save a bit of memory and cache footprint. Same for the ILP32 ABI on AArch64.

So, for guesstimating memory use, you can use your assumption and it will often be right.