Q:

More than one conditional compilation symbols?

I have a question regarding conditional compilation symbols in Visual Studio (my version is 2017).
Assuming that I have two compilation symbols, e. g.:
#if new_version
#if old_version

then in what typing should I put them in Project properties ->Build ->Conditional compilations symbols:
1) new_version, old_version
2) new_version;old_version
3) new_version; old_version
4) new_version,old_version
5) other options?
Any suggestion which way is correct?

A:

Use semi-colons, but I would think with names like new_version and old_version that you would generally only define one of them.

