A software bug is an error that happens in an application causing it to return an invalid result or to function incorrectly. A bug can result from incorrectly written code, errors in a compiler, or even hardware issues. In this article, w'll be looking at code-specific bugs because those are usually created inadvertently by programmers.
Don't worry if the code you write has bugs. It's expected. Bugs are an inevitable part of writing code. Even developers with years of experience have probably never written a bug-free application. Once bugs are found in an application, developers use a process called debugging to track down what is causing those errors and find a fix for them.
You can use quite a few methods to debug software depending on the tools you have available, your level of skill, and the complexity of the bug. Mike, a developer from Philadelphia, talks about debugging code in the video below. Take a look, then read on to learn more.
6 code debugging techniques
You won't have to use every one of these debugging techniques to fix a bug. Some are simpler than others to implement. It's usually best to start with the simpler techniques that only take a few minutes to set up and then proceed to more complex techniques if you still have not tracked down the bug.
Using a print statement might be the simplest way to debug code. All programming languages have one or more commands that you can use to print values out on the console when the software is running. Once you have tracked down where you think the bug is occurring in your code, you can add a print statement to print out the value of the variables around the bug to determine why the bug might be happening.
Another method of debugging your code is using error handling. Code that does not use error handling will often crash when it encounters a bug. Error handling catches an error before it has a chance to crash the application. It then does something with the error data, like logging or storing it in a database, and the application then continues normally.
Error handling is perfect for finding bugs in a production environment because errors can be collected as they occur and then analyzed later to determine what type of bug is causing them — all without causing a bad experience for the software user.
Commenting things out
Another simple method of debugging is "commenting out" some of the code. This means turning some of the functional code into comments that won't be executed. You start by commenting out code in the part of the application where you think the problem is until the error stops happening. Then you just add each line of code back, one at a time, until the bug shows up again, and once it does, you've pinpointed where the bug is occurring.
Debugging tools are the most sophisticated way of finding bugs in software. These are usually built into the integrated development environments (IDEs) developers use to write code. There are also debuggers that come with some of the web browsers, including Chrome and Firefox, for debugging web applications.
Debuggers allow programmers to create "breakpoints" in code. When they run code with a breakpoint in it, the code will stop running at the breakpoint. The developer can then step through the code line by line and examine the variables in each step to determine what went wrong. Using a debugger is the best way to find the hardest bugs, but it is also the most advanced method and is not needed when other techniques will work.
Another way of debugging your code is by adding code tests. These come in many varieties and include unit tests, integration tests, functional tests, and more. These types of tests are created to check that the application is running correctly. The tests are run on the application code before it is added to the code repository or deployed to production. When the tests do not pass, it usually indicates a bug that has to be fixed. The code that failed is not allowed to move onto the next phase until the bugs are fixed and the tests pass.
Asking other developers
While this is the last method on the list, it's one of the most important and is often overlooked. Most times, you will be working with other developers on the same project who may know more about some of the code than you do. Even if they don't, they may have worked on the part of the application that has the bug. But you won't know unless you ask.
Another reason to ask other developers for help is that after you look at the same code for a while, you may be too close to the problem and choose the wrong route to a solution. Even if the developers you ask don't work on your project, they can often help you find the bug by giving you a fresh perspective.
Bugs are part of the software development process. So if there is a bug in the code you wrote, you're in good company. Even developers with years of experience expect to deal with bugs. Luckily, there are many ways to debug your code and fix it.
Simple methods you can start with include using print statements to print out variables or commenting out part of the code until the error goes away. Using a debugging tool is an advanced method that will allow you to stop the code and inspect it as it is running. Adding tests to your code can help find bugs before they go to production. You can use error handling to report production bugs that you would rather not have users see. Of course, one of the best debugging procedures is simply asking other developers if they know what could be causing a bug and point you in the right direction.
The best way to learn code debugging is by writing code. If you are interested in building web applications, check out either our Back-End, our Front-End, or Full-Stack Engineer Career Path. For even more possibilities, check out our complete catalog of programming courses.