The Source of Readability

I'm going to push back somewhat on global variables. I think they can actually be very helpful when you are working in the debugger, particularly with memory dumps. Instead of looking across a bunch of different threads, you can inspect globals directly.

In terms of not wasting vertical space, I think you'll run into issues since it starts to conflict with readability from familiarity. People aren't used to having a bunch of statements on a single line so they may not notice it. There's a similar phenomenon with reading research papers where it is very time consuming initially because you may be unfamiliar with the structure, but after a while, you can read them very quickly since you know what to skip over and what to pay close attention to.

I break two of these all the time: minimize vertical space and define variables close to their use.

I'm one of those people that prefer braces on their own mine, even left braces.

But it works for me. Empty space actually helps me read my code more easily.

Likewise, in C, I define all variables at the top of a scope. This is dangerous in C because of the possibility of uninitialized data, but Clang catches everything. And I prefer it because Clang has a warning to enforce that style so that I can't mix styles. Also, using those variables becomes like using type inference in other languages; the first use looks like initialization without the type annotation.

Not that the author is wrong, but don't feel bad if you depart from this for your own personal stuff. And follow whatever style policy is required by your employer.

To novice, most of these are guidelines, don't treat them as rules. If something feels wrong to you, you are free not to follow them. Also almost always follow the conventions of your team/project. Nothing is worse than multiple coding styles in a project, unless whole team finds it better and decides to follow it.

Clear naming will give you most ROI. When you have confusion follow the simplest path, it is always easier to refactor simple code later.