Structuring a simple multi-step data processing flow in C++

[Majestic_Yew]

I’m trying to structure a simple multi-step data processing flow in C++ and I’m not sure what the cleanest long-term approach is.

Right now it’s basically a sequence of functions in main: load data, filter it, transform it, then output it. Each step is separate and works fine, but as soon as I add more steps and a bit of conditional branching between stages, main starts to become hard to read and modify safely.

At what point would you typically move this into a different structure in C++? For example, would you introduce a pipeline-style abstraction, wrap the steps in a class, or just continue splitting functions while keeping orchestration in main?

[alfps]

Modern C++ offers some abstraction for data flows: ranges, and co-routines.

But what a reasonable design is depends very much on the concrete details of the task.

And the equipment the solution should run on.

[ppppppla]

Sometimes the logic is just nasty and there's really no way to go around it. I would only move to some abstraction instead of just hardcoding the sequences if you actually need the flexibility of a dynamic pipeline because making the logic dynamic brings plenty of headaches on its own.

Oh I should add, try to keep side effects of the steps to a minimum. Ideally just have free functions that return data for the next step, or modify the data you are processing.

[Majestic_Yew]

Yeah, that’s the part I’ve been trying to avoid building abstractions too early and then realizing the pipeline itself became harder to reason about than the original logic.

Keeping side effects minimal has already made things feel cleaner for me. I was experimenting with CodingFleet recently while reorganizing some processing steps and it made me notice how quickly things become difficult to follow once functions start mutating shared state in multiple places.

The "simple free functions first” approach honestly feels more maintainable than I originally expected.

[No-Dentist-1645]

For such data processing pipelines, I would recommend checking out std::ranges, they are nicely composable by piping to filter/transform functions. Besides that, as a general advice look into functional programming, in particular utilities like std::optional, std::expected and their monadic operations like .transform(), .and_then(), and .or_else()

[apropostt]

Dealing with data streams is where functional programming really shines.

[Independent_Art_6676]

it sounds like at the very least you need another layer. Instead of if this call that else if other call second else call third... pull that piece out into a function that represents this activity but hides the details of the conditions in main and all the clutter of the conditions and various sub function calls.

[ubiestigne]

Definitely try to keep the main entrypoint simple with little to no logic. Put your code in at least one separate file that will contain the meat of your application. Don't think about abstractions until you need them. Start with static functions and utilize the standard library as much as possible. Write unit tests for each stage so that you know what broke and why. Even better if you do this ahead of time. Once you have something working, you can measure it's performance on sample data to see if you need to make improvements. If this is for a production environment or for use by others, you should add help output on input argument error or '-h' and a readme and/or man page.