Design & Coding - top to bottom or bottom to top? [closed]

Answer 1

Here's what I do:

Understand the domain first. Understand the problem to be solved. Make sure you and the customer (even if that customer is you!) are on the same page as to what problem is to be solved.

Then a high level solution is proposed to the problem and from that, the design will turn into bubbles or bullets on a page or whatever, but the point is that it will shake out into components that can be designed.

At that point, I write tests for the yet-to-be written classes and then flesh out the classes to pass those tests.

I use a test-first approach and build working, tested components. That is what works for me. When the component interfaces are known and the 'rules' are known for how they talk to each other and provide services to each other, then it becomes generally a straightforward 'hook everything together' exercise.

That's how I do it, and it has worked well for me.

Answer 2

Also in the agile way, write your test(s) first!

Then all software is a continual cycle of

• Red - the code fails the test
• Green - the code passes the test
• Refactor - code improvements that are intention-preserving.

defects, new features, changes. It all follows the same pattern.

Answer 3

When designing, I like to do middle-out. I like to model the domain, then design out the classes, move to the database and UI from there. If there are specific features that are UI-based or database-based, I may design those up front as well.

When coding, I generally like to do bottom-up (database first, then business entities, then UI) if at all possible. I find it is a lot easier to keep things straight with this method.

Answer 4

Your 2nd option is a reasonable way to go. If you break the problem down into understandable chunks, the top down approach will reveal any major design flaws before you implement all the little details. You can write stubs for lower level functionality to keep everything hanging together.

Answer 5

Yes. Do all of those things.

It may seem sarcastic (sorry, I revert to form), but this really is a case where there is no right answer.

Answer 6

I tend to design top-down and implement bottom-up.

For implementation, building the smallest functional pieces and assembling them into the higher-level structures seems to be what works best for me. But, for design, I need to start from the overall picture and break it down to determine what those pieces will be.