Shifting Styles

To say it’s been some time since I last posted is an understatement! I won’t bore you with the details other than to note that sometimes there just aren’t enough hours in a day.

Anyway, today’s post is about a stylistic issue I’ve noticed in just about all code I’ve ever looked at. Unless you are a closeted BASIC programmer, you probably don’t ever write something like this:

foo = foo + 6;

While there’s nothing particularly wrong with this, other than looking rather odd from a mathematical perspective, just about every C programmer would use the += operator, i.e.

foo += 6;

Indeed this is true for all the arithmetic and logical operators. I.e.

foo *= 6;
foo /= 6;
foo -= 6;
foo ^= 6;
foo |= 6;
foo &= 6;

However, when it comes to the shift operators, something odd seems to happen. Almost no one writes:

foo >>= 6;

or even rarer:

foo <<= 6;

Instead folks resort to the syntax of BASIC and use:

foo = foo >> 6;
foo = foo << 6;

Why exactly is this? This thought was triggered by me looking at some of my own code from about ten years ago. Sure enough right in the middle of what was an otherwise well written piece of code (in the sense that ten years later it was easily followed and was a breeze to adapt to my latest project) I found a:

foo = foo << 6;

I have no real explanation other than we are all creatures of habit and sometimes get into inconsistent programming styles. While I wouldn’t fault someone for doing this, I do think that if you quite happily use += but not >>= then you should ponder your rationale for being inconsistent. Perhaps it will trigger a bigger introspection?

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