Code documentation is one of the most important aspects of a software project. It helps us create a knowledge base that explains how anything or everything works in software. In this article, we will discuss the basics of code documentation with examples. We will also discuss some code documentation tools and techniques.

What is Code Documentation?

Code Documentation is the umbrella term that encompasses all written documents and materials dealing with a software product’s development and use. It is the process of creating written or visual materials that provide information about the purpose, functionality, and usage of the software. 

Documentation serves as a valuable resource for developers and users to understand, utilize, and modify the codebase effectively. Good documentation enhances code comprehension, facilitates collaboration, and assists in troubleshooting and debugging.

Why Do You Need Code Documentation?

A code is written once but read and modified multiple times. Hence, it is important to document each and every component of the code. This helps you and your team to maintain and modify the code in the future.

• If you read a code after writing it months ago, it is possible that you won’t even remember what the code does. In this case, you will be in a helpless situation as no one can explain to you what the code is all about. To avoid such a scenario, you must document the code in a way that explains the context, use cases, and all the components in an extensive manner.
• You will not be working in a single company or even a single project all your life. After you leave a project, other developers will maintain and add new features to the code. Hence, it is important for the developers to know the functionality and implementation of each component in a project in a detailed manner. To fulfill this requirement, you need to create detailed documentation explaining the functions and algorithms used in the code. 
• There can be many components such as functions and classes in your code that other developers can reuse. If your code is well documented and contains the context, definition, and implementation details of each component, other developers can reuse the code. This will help your team save precious time and will avoid duplication of work.
• Good documentation provides transparency in the development process. If the design, algorithms, and implementation of the code are documented properly, anyone can read it and understand what the code does.  This will help them in reusing the code as well as fixing bugs when they encounter any errors.

Components of a Code Documentation

Code Documentation can take various forms. You can use comments within the code, separate documentation files, or even automated tools that generate documentation from the code itself. Following are some of the key components that you should include in code documentation:

1. Purpose and Overview: Documentation often begins with an introduction that explains the purpose of the code. In this section, try to describe the intended functionality and the problem that your code aims to solve. You should also include an overview of the codebase’s structure and organization.
2. Installation and Setup: This section outlines the steps required to install and configure the code. It includes dependencies, prerequisites, and any specific environment variables or configurations needed to run the code successfully.
3. Usage Instructions: Code documentation should describe how to use the code, including available functionalities, input/output specifications, and possible customization options. For this, you can provide code snippets or examples demonstrating typical use cases.
4. API Reference: For libraries or frameworks, you should create detailed documentation for the exposed application programming interfaces (APIs). Here, you should cover the available classes, functions, and methods with their parameters, return values, and usage patterns.
5. Code Structure: Documentation may delve into the codebase’s internal structure, modules, and components. You can explain the relationships and dependencies between different components of the code. This will help the developers navigate the codebase efficiently.
6. Configuration: If the code relies on configuration files or settings, you should outline the available options, their effects, and how to modify the configuration to suit specific requirements.
7. Troubleshooting and FAQs: Your code documentation must include a section that addresses common issues, error messages, and their potential resolutions. You can also include a list of frequently asked questions (FAQs) to assist users in resolving common queries.
8. Contributing Guidelines: In open-source projects, documentation often includes guidelines for contributing to the codebase. This includes coding conventions, testing procedures, and information about the development workflow.
9. Changelog: For evolving projects, a changelog highlights significant changes made to the codebase in different versions, helping users understand new features, bug fixes, and potential breaking changes. You should always document the changes made in the code with proper explanation.
10. Examples and Tutorials: In the code documentation, you may include comprehensive examples, use cases, and step-by-step tutorials. This will help you demonstrate the code’s capabilities and will guide the users in implementing specific functionalities.

How To Document Your Code?

Code documentation goes along with development tasks. You can use the following code documentation steps for better results.

Write Clean Code

Writing clean code is the first step toward creating maintainable software. You should always try to follow proper naming conventions for variables, functions, files, etc. To create reusable code components, try to create functions, classes, and methods with high cohesion and low coupling. This will also help you reduce redundancy in the code. You should also review your code and refactor it from time to time.

Suggested reading: Code refactoring techniques

Add Proper Comments To Your Code

Comments are one of the easiest ways to describe the code in an understandable manner. A comment should clearly explain what a code is doing and why it does so. You should also try to format the comments for better readability.

Document Test Cases

We often write unit tests to test different modules in our code. The unit tests provide us with an idea of how code should behave. Hence, if the code passes all the unit tests, it is highly likely that the code will not run into errors. 

While creating documentation, you should also document all the test cases used for unit testing. This will help you keep track of the functionalities in the code. Additionally, it will also help any other developers in the future if they modify the code and want to re-run the unit tests. Clearly documented unit tests will make their task easier.

Use Proper Commit Messages

While committing your code to the git repository, make sure that you describe the changes using proper commit messages. This will help you debug your code or identify any possible errors if the code runs into an error after a commit.

Maintain Readme File in Code Documentation

While documenting your code, always create a readme file with all the instructions to use your code module. The readme file should contain the following information.

• A short description of the code module. 
• Instructions for installing and running the project.
• Versioning and license.
• An explanation for the directory structure of the code and its contents.
• Known issues and credits if any.

Create Good Short Notes While Writing Code

As you plan to code, you should take notes of different things that can help explain things in the future. While you are coding, you must keep a text editor open and record the following things.

• Why you chose an algorithm over another if there are multiple possible ways to complete a task? This will help you explain the code in a better way.
• All the Stackoverflow and blog links that you visit while coding different components of your program.
• Challenges and errors you ran into while coding.
• System configuration changes and command line prompts if used.
• The order in which you coded different components and why. This will help you explain your thought process while documenting the code.

Explain Your Decisions in The Documentation

Once you have coded two or three snippets, explain the decisions taken while coding in long form. You should document all the ideas and decisions that are mentioned in the short notes. Here, try to explain each component in the short notes as if you are teaching this to someone else. 

Mention Prerequisites For the Code

Documentation should contain all the links to prerequisites for the tools you are using. Links to things like installation steps, support issues, README files, API documentation, etc should be included in your documentation. For terminal commands, explain the syntax and use case so that someone who is reading the documentation gets an idea of the actions without the need to search the internet or man pages. 

Code Documentation Tools

Code documentation in a simple text editor can be cumbersome as you need to format the code, algorithms, etc. Hence, you should try to use different code documentation tools. Following is a list of code documentation tools for different programming languages.

• For Python, you can use the following code documentation tools.
  • Sphinx
  • Numpydoc
  • Doctest
  • Doxygen
• If you code in Java, you can use Javadoc.
• For C++, you can use the following code documentation tools.
  • Doxygen
  • BoostBook
  • QuickBook
  • GhostDoc
• For R codes, you can use R Markdown and Kite as your code documentation tool.

Conclusion

In this article, we discussed the basics of code documentation. We also discussed different tools and techniques for code documentation. To learn more about coding, you can read this article on the zen of Python. You might also like this article on the best Python debugging tools.

I hope you enjoyed reading this article. Stay tuned for more informative articles.

Happy Learning!

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