What is Debugging? What is Debugging Used For?

First of all, debugging doesn't mean looking at your screen and wondering why your computer hates you. 🤭

Debugging refers to the process of tracking and eliminating problems in software applications such as bugs and security vulnerabilities that may arise due to poor coding, architecture, or implementation. 

The purpose of debugging is to fix these problems to ensure that the software behaves as intended and operates reliably. These errors can lead to application or system failures, poor performance, or incorrect results. 

Yes, the debugging process can be time-consuming and frustrating. However, it is very important for the proper functioning of the system and the program. That is, debugging is an important part of software development. We can say that it is essential to maintain code writing quality and optimize performance.

This process is not just about correcting coding errors that cause a computer program to crash. It also involves solving problems that lead to incorrect or unexpected results.

Debugging can be performed using many other methods, such as keeping logs, running in small, controlled units (testing), or statically examining the code (code review and static analysis). In the following parts of the article, we will also address some tools and techniques. 👇

How Did the Term “Debugging” Originate?

While the term "bug" was used for mechanical failures, it was first used in computers in this sense by Admiral Grace Murray Hopper in the 1940s. 

When Hopper and her team found a moth in the computer they were working on, they called this situation a "bug." 🪲 So, this term has a very real origin. Fortunately, the days when we had to remove real bugs from computers are long gone. :)

Hopper is also known as the person who wrote the first compiler. The term "debugging" was actually used earlier in aviation, and there is evidence that even Thomas Edison used this term in 1878 to mean a technical error.

What Are the Types of Errors in Software?

There are various types of errors that can cause the application not to do what is expected or not to work at all. We have listed some of them below:

Syntax Errors

Syntax refers to the "rules" that define a programming language. Therefore, syntax errors result from breaking the rules of the programming language. A mistake in a parenthesis, comma, or typo can cause you to search for errors for hours. 🤭

Logical Errors

A logical error occurs when the application does not work as it should. To be more specific, such errors technically consist of correct syntax but with misdirected logic. Let's look at the example below:

In the above for loop, we are trying to generate all even numbers less than 10. When the above code runs, it gives these even numbers: 2, 4, 6, 8, and 10. 

But there's a problem with the results. Numbers less than 10 should even include the number "0". We are missing the first even number, zero, because we set our loop to start from 1 instead of 0. Logical errors like this can be hard to detect since the syntax is correct. 

Runtime Errors

A runtime error occurs when the application stops during execution. Sometimes, runtime errors may result from the environment in which we run the application. Or it may be a signal of another type of error, such as a logical error that requires more memory.

Debugging Steps

There are five simple steps we can follow to really understand debugging and make it more manageable and perhaps enjoyable:

Step 1: Gather information about the error
As a beginner developer, it's inevitable that you'll make typos. You might even describe it as the most time-consuming and daunting phase of programming. Therefore, considering such errors should be among your priorities. You can try to read and understand error messages. 

Step 2: Find the source of the error

In this step, try to determine the source of the error. Even a tiny semicolon can cause you to search for the error for hours. You may need to "reproduce" the error to understand when it occurs. Also, by commenting out some parts of your code, you can see which part of the program is causing the error. 

Step 3: Identify the error
After narrowing down the area where the error occurs, you need to determine exactly what the error is. You can form a hypothesis for this. For example, if you notice that the error originates from a form field, you might think that you used the wrong data type. 

Step 4: Determine how to fix the error
After forming your hypothesis, you can move on to the testing phase. You need to repeat this until the error is fixed. Sometimes, the solution may not be immediately apparent; in this case, you can research solutions to similar errors on platforms like StackOverflow. If you wish, you can also ask for help from other developers on the Coderspace Discord server. 

Step 5: Implement and test

Run your code again to see if the error has been fixed. Testing is an effective way to ensure that you didn't cause other problems while fixing the error. 

Sometimes, despite all your efforts, you may not be able to completely solve the error. In this case, you can find a temporary solution to keep the application running.

Finally, don't forget to document your solution. Documenting the solution will make your job easier if you encounter the same problem again.

What Are Debugging Strategies?

As a developer, debugging is part of your daily work. How often does it happen? Almost every day. 😱 In this case, what can you do to make debugging faster, more efficient, and even enjoyable?

1. Active Debugging
 

This technique involves reducing the lines of code you will debug. One way to do this is by commenting out parts of your code to narrow down the source of the error.

2. Adding Print Statements

You can add print statements after every few lines or after a single line to narrow down where the error is.

3. Using a Debugger

You don't have to find all the errors yourself. You can use tools that help you find errors, called debuggers. Some IDEs (Integrated Development Environments) and text editors already have built-in debuggers. You can also take advantage of them.

4. Using Breakpoints

Breakpoints are points that halt the execution of your code. However, these are not due to an error; they are points where developers intentionally stop execution. By adding breakpoints to your code, you can simplify the error detection process. These breakpoints can be added to IDEs, text editors, or browser developer tools.

5. Writing Tests

All the techniques we've examined so far can be called "reactive debugging." Writing tests is "proactive debugging." 

Developers write a simple test program that simulates what the program will do before writing code. For example, tests can be run using libraries like Mocha or Jasmine for JavaScript, and errors can be detected and fixed. With this method, you create a "sample" of the code you need to write.

Debugging Tools

Debugging tools are software programs used to identify, test, and debug issues by other programs. These tools provide detailed information about application execution, memory usage, variables, and other related data, offering a systematic approach to troubleshooting and debugging software issues. 

Let's not forget that the best debugging tools often depend on the specific requirements of the project, the development environment, and the personal preferences of the developers.

Let's take a look at debugging tools 👇.

Debuggers

Debuggers offer features that help developers monitor the execution of code and determine the root causes of unusual behavior or errors. Although standalone debuggers are available, some IDEs like Visual Studio include built-in debuggers.

Some commonly used debuggers include:

• GDB (GNU Debugger): A portable debugger that works for many computer programming languages, including C and C++.
• PDB (Python Debugger): A debugger for the Python programming language.
• JDB (Java Debugger): A command-line debugger for Java programs.
• Visual Studio Debugger: A powerful debugger integrated into the Microsoft Visual Studio IDE, primarily for .NET languages and C++.
• Chrome Developer Tools: A set of web developer tools built directly into the Google Chrome browser, including JavaScript debugging capabilities.
• Firebug: A once-popular but now discontinued web development and debugging tool for Firefox.
• Xdebug: A PHP extension for powerful debugging and profiling.

Version Control Systems

You've probably used GitHub to store your code. If so, you've encountered Git, the version control system that makes it possible to track code changes. Git can help you debug, load previous versions of the code, and compare different versions of the code. 

Test Frameworks

Unit test frameworks, while often used for testing, can also help with debugging. They give developers the ability to create and run automated tests that isolate specific areas of the software. There are numerous unit test frameworks. The choice of tool depends on the programming language, development environment, and specific debugging requirements.

Browser Debugging Tools

Most browsers have debugging consoles. In Chrome, there are Chrome Developer Tools, and in Firefox, there are Firefox Developer Tools. You can access them by pressing F12 on Windows and Linux, or Cmd + Opt + I on macOS.

AI Debugging Tools

Thanks to Artificial Intelligence (AI), we now have more options to assist with debugging. You can use generative AI tools like ChatGPT to simplify the error-finding process. ChatGPT can even suggest how to fix the error. You can also get help from AI coding tools like GitHub Copilot and codeQL.

Debugging vs. Testing

Testing and debugging are complementary processes in development. Although they have different outcomes, both testing and debugging are used to produce error-free code.
Testing allows software developers to understand what happens to the system when errors occur. These tests help developers know when a system fails and the impacts of the error on a piece of software. 

Essentially, testing is an important part of software development, but it does not explain why an error occurs. This is where the term debugging comes into play.
Debugging strategies and tools are what developers use to find, fix, and prevent errors from reoccurring. 

Debugging and testing complement each other. When used together, they help teams develop code and create better software products.

The Debugging Process

The last part of truly grasping what debugging is involves knowing how to prevent errors in the first place. 

The truth is, there won't be a day when you write 100% error-free code. Your goal should be to write code with as few errors as possible. In this case, when errors occur, finding them can be easier. 

We hope you're now ready to make error-finding fun and, better yet, to write code with much fewer errors.

If you want to start coding from scratch, you can check out our Technology Schools trainings and access more detailed information about the debugging process.