When evaluating a design, how do you evaluate complexity? [closed]

Question

We all know to keep it simple, right?

I've seen complexity being measured as the number of interactions between systems, and I guess that's a very good place to start. Aside from gut feel though, what other (preferably more objective) methods can be used to determine the level of complexity of a particular design or piece of software?

What are YOUR favorite rules or heuristics?

Answer 1

Here are mine:

1) How hard is it to explain to someone who understands the problem but hasn't thought about the solution? If I explain the problem to someone in the hall (who probably already understands the problem if they're in the hall) and can explain the solution, then it's not too complicated. If it takes over an hour, chances are good the solution's overengineered.

2) How deep in the nested functions do you have to go? If I have an object which requires a property held by an object held by another object, then chances are good that what I'm trying to do is too far removed from the object itself. Those situations become problematic when trying to make objects thread-safe, because there'd be many objects of varying depths from your current position to lock.

3) Are you trying to solve problems that have already been solved before? Not every problem is new (and some would argue that none really are). Is there an existing pattern or group of patterns you can use? If you can't, why not? It's all good to make your own new solutions, and I'm all for it, but sometimes people have already answered the problem. I'm not going to rewrite STL (though I tried, at one point), because the solution already exists and it's a good one.

Answer 2

Complexity can be estimated with the coupling and how cohesive are all your objects. If something is have too much coupling or is not enough cohesive, than the design will start to be more complex.