c++ - Does sizeof evaluate at compile-time or runtime?

Question

I am confused about the evaluation time of sizeof operator.
When does the sizeof operator get evaluated?

Does its evaluation time (compile-time or runtime) depend on the language (C? C++?)?

Can we use sizeof in case of objects created at runtime in C++?

Answer 1

In almost all cases, sizeof is evaluated based on static type information (at compile-time, basically).

One exception (the only one, I think) is in the case of C99's variable-length arrays (VLAs).