Cppcoreguidelines: Add space after #include-statement

[larsch]

I propose to add a space after #include statements in examples.

• It's the industry convention on most if not every codebase I have come across:
• It's the convention followed by Google (Chromium, Protobuf, ...), Apple (LLVM), Microsoft (Chakra)
• SF.1 also uses "longstanding convention" as a argument. If applied to NL.15, there should be a space.
• It is the convention in "The C++ programming language"
• It is the convention in "The C Programming Language"
• NL.17 says to use K&R style
• SF.9 has a space after #include (albeit it's the only entry that uses quotes)
• #include"foo.h" just looks weird
• Using the NL.15 argument for omitting the space is inconsistent with NL.17 which tell you to put space after 'if'

[galik]

I'm not sure about all of those arguments but the killer argument for me is:

• #include"foo.h" just looks weird

😀

[MikeGitb]

I fully agree. I faintly remember that there was already some discussion around this issue somewhere in the context of the NL.15 example, but I didn't realize this style has spread throughout the whole document.

Also important is the note in NL.15:

We value well-placed whitespace as a significant help for readability. Just don't overdo it.

[galik]

BTTT Just wondering if this issue got overlooked?

[AndrewPardoe]

Done, thank you.