CSI Code: Difference Between Refactoring and Debugging

Development sometimes feels like a never-ending process, doesn’t it?

As QA finds new bugs, you need to debug and fix them. And after you fix it, it is an excellent software engineering practice to refactor the code to improve it.

Debugging and refactoring are two everyday software development activities, but what is the difference between them?

Debugging is the process of finding and removing bugs from the code. Refactoring is an improvement to the internal structure of the code without changing its behavior. Debugging focuses on correcting errors in the code, while refactoring focuses on improving the code’s design.

This article will cover what refactoring and debugging are, why they’re essential in programming, and how you can use them when coding.

What is Debugging?

Debugging is the process of finding and removing the causes of software bugs. For example, when an application is running, a user will often see the bug and report it to the development team. Therefore, a developer assigned to remove the bug needs to find the root cause.

During the debugging session, the developer needs to find out why the bug is happening and find a way to fix it. He can do that by deleting, modifying, or adding new code to change the original behavior. To be able to debug, a developer needs to use different tools such as a debugger, an editor such as Visual Studio or VS Code, and conditional breakpoints.

Debugging is one of the essential skills you can learn in programming. Finding bugs in your code and fixing them separates good programmers from great ones.

Debugging is also a lot like solving a puzzle or a mystery. You have to think about all the pieces of information at your disposal and how they might be related. That’s why debugging can be fun and frustrating at the same time. It’s like getting an insight into the inner workings of a complex piece of software to find the error. This is especially true when you work with legacy code. You may find debugging is like exploring uncharted territory.

Debugging is an essential process of software development because, without it, programmers wouldn’t be able to fix bugs in the code, and their programs would be defective. However, debugging can be a tedious process. But it’s a needed activity.

What is Refactoring?

Software design and development is not just about writing code. It’s also about understanding the code that has been written. And it’s also about improving the existing code. And that’s what refactoring is all about.

Refactoring is a process that involves changing the internal structure of software without changing its external behavior. This also includes improving the design to make code more readable, maintainable, and reliable. A typical example of this is converting code that uses nested if-else statements to a single-nested if statement, which is easier to read and debug. Another example is using refactoring to remove duplicate code.

Why should you refactor your code? You should refactor your code to maintain a high coding standard and remove the technical debt from it. Developers can also refactor code to improve its performance. For instance, if the developer needs to make it faster, he can look for unnecessary method calls that slow down the execution.

Many IDEs now come with built-in refactoring capabilities.

Refactoring shouldn’t change how the application works. But if the changes are made during the refactoring process that alters the existing code’s external behavior, that’s not refactoring anymore. And when this happens, the developer has two options:

  • He can execute all the unit tests to make sure he hasn’t broken anything.
  • He can undo the refactoring changes and try something else.

The preferred option is the second one. Don’t change the behavior of the existing code without the need to change it. You might introduce additional bugs.

Refactoring is a crucial skill for developers to have. It allows them to clean up code that has become messy over time. Refactoring also helps developers ensure that they are coding in the most efficient way possible, saving time in the long run.

The ability to spot an area in the code base, also known as a code smell, that needs refactoring is critical for developers.

Ideally, developers should keep the code clean and organized at all times. However, this doesn’t always happen. Sometimes, you don’t have time to refactor as soon as you implement the changes. But it’s important to refactor the code the next time you need to work with it.

The difference between debugging and refactoring

Debugging and refactoring are two closely-related terms that are often used interchangeably. However, they refer to two completely different activities.

Many people don’t know that you can use debugging and refactoring together to solve a problem despite the differences in objectives.

For example, let’s say you’re working on a website where users can create accounts and log in. You’ve spent days writing code for the entire project, but something isn’t working as expected. The user login button doesn’t disable once a user clicks on it to log in. You can do much more instead of just fixing it by adding some Javascript code. Before fixing a bug, you can do some refactoring to make the source code easier to change. Then make the change by debugging and fixing the issue. Once you fix the issue, refactor some more if you find the opportunity. Finally, perform unit testing.

As you could see in the above example, debugging and refactoring are different processes with different goals:

  • Debugging is the process of finding and fixing a bug in your code.
  • Refactoring is reworking your code to make it more efficient and easier to maintain. Unlike debugging, refactoring does not involve fixing bugs or errors.
  • Debugging involves changing the behavior of the application.
  • Refactoring doesn’t change the behavior of the application.

Debugging and refactoring are essential programming practices that programmers use to improve their code.


Bugs and errors in code are a part of programming life. Software is complex, and the more complex it is, the more bugs there are. Debugging and refactoring are two entirely different things, but they get mixed up because they aim to fix code.

Debugging is fixing broken code. You take an existing piece of software and try to find out what went wrong. You’re essentially looking for a needle in a haystack.

Code refactoring is the process of changing bad code into good code without changing its external behavior. You’re improving the code without changing what it does.

Refactoring and debugging are essential skills you should use to have a great code. If you are interested in learning more about refactoring code, I highly recommend the following articles with practical techniques and code examples:

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