I'm at the point where I can build small programs, but I still can't always tell what went wrong just by reading the code. My usual approach is to add print statements throughout the program to check whether each line produces the value I expect. It works, but the output becomes difficult to manage, and removing or cleaning up all the temporary prints takes time. Is there a more beginner-friendly way to track how variables change and identify which line caused a problem? I mainly use Python with VS Code, and I also work with C++ and Bash.
5 Answers
For deployed programs, structured logs and feature flags are more useful than interactive debugging. A feature flag can enable extra diagnostic information only when needed, while normal logs record errors and important events. Good logs should include enough context to understand what happened later without flooding the output.
The main tool you’re looking for is a debugger. Set a breakpoint where you suspect the problem is, run the program in debug mode, and step through it one line at a time while watching variables, the call stack, and function results. You can usually choose whether to step into a function or step over it. VS Code has debugger extensions for Python and C++, so it’s worth following a short tutorial for each language. It feels unfamiliar at first, but it becomes much easier once you understand the basic controls.
There’s nothing wrong with using print statements while you’re learning. They can actually teach you a lot about how data flows through a program. For temporary diagnostics, though, a debugger lets you inspect values without changing the code. A useful habit is to combine that with small assertions or tests, so you can quickly confirm which function is producing an unexpected result.
I still use print statements for quick checks, especially when adding a breakpoint would take longer than running the program. They’re also handy when debugging many steps across several files or code that takes a long time to compile. The important part is to make them easy to remove or disable, such as putting diagnostic output behind a debug flag. For more complicated local bugs, I switch to the IDE debugger.
Logging is a good middle ground between prints and a debugger. Use levels such as debug, info, warning, and error, and include useful context in each message. Then you can turn verbose output on during development and leave it disabled or restricted in other environments. In Python, the built-in logging module is a good place to start. You can also use a DEBUG flag or a verbose command-line option for small scripts.
I was worried that I’d still need to add and remove lots of breakpoints, and that the learning curve would be steep. Is there a particularly beginner-friendly debugger setup?