Good, I think? It wouldn't be a deal breaker at interview for me (or even something we test for, come to think of it), but they were right in that it is a magic number. Unless you are doing something where the context is so perfectly obvious that number should be an 8, it's better off tagged as a constant so the next dev to come along has a better chance of understanding your code.

Indeed:

  static const int eight = 8;

  x * eight;

Sometimes magic numbers are just that - numbers. Adding constant definitions is often a good thing, but sometimes just adds noise.

I think you mean

    static const int days_per_week = 8;

:-).