💬 Go Comments – Write Clear, Readable, and Documented Go Code

🧲 Introduction – Why Comments Matter in Go

Comments are essential for writing readable, maintainable, and documented code. While Go emphasizes simplicity and self-documenting syntax, comments still play a key role in explaining the “why” behind your code decisions.

🎯 In this section, you’ll learn:

• How to write single-line and multi-line comments in Go
• Best practices for using comments effectively
• How Go uses comments in tools like godoc
• What not to do when commenting your code

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✍️ Types of Comments in Go

Go supports two comment styles, both borrowed from C/C++:

✅ Single-line Comment

Begins with //. Everything after // on that line is ignored by the compiler.

// This is a single-line comment
fmt.Println("Hello, Go!")

Use this for brief explanations, annotations, or temporary code disabling.

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✅ Multi-line Comment (Block Comment)

Enclosed between /* and */. Useful for longer or multi-line commentary.

/*
This is a multi-line comment.
It spans multiple lines and is ignored by the compiler.
*/
fmt.Println("Welcome to Golang")

⚠️ Note: Multi-line comments cannot be nested in Go.

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📚 Commenting for Documentation

Go has a powerful documentation tool called godoc which generates docs from your code comments. To make use of it:

• Add doc comments just above functions, types, variables, or constants
• Begin with the name of the item being described

Example:

// Greet prints a greeting message to the user.
func Greet(name string) {
    fmt.Printf("Hello, %s!\n", name)
}

When you run:

godoc -http=:6060

You can view your documentation in a browser at http://localhost:6060

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🧠 Best Practices for Comments in Go

✅ Do:

• Use comments to explain why something is done, not what (the code already shows that).
• Document public functions and types using doc comments.
• Keep comments up to date as the code changes.

🚫 Avoid:

• Writing obvious comments: i := 0 // Set i to 0 ← Redundant
• Leaving old, misleading comments in code
• Over-commenting — clarity should come from clean code

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🧪 Example – Combining All Comment Types

package main

import "fmt"

// main is the entry point of the application
func main() {
    /* Display a message to the user.
       This is an example of a multi-line comment. */
    fmt.Println("Comment examples in Go!")
}

Output:

Comment examples in Go!

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📌 Summary – Recap & Next Steps

Go makes commenting simple and powerful, especially when combined with tools like godoc. Well-placed comments improve code clarity and serve as in-code documentation.

🔍 Key Takeaways:

• Use // for single-line and /* */ for multi-line comments
• Avoid redundant comments; explain intent, not syntax
• godoc uses comments to generate rich documentation
• Comments should evolve along with your codebase

⚙️ Next: Learn about Go’s Fmt Package and how to format data in output.

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❓ FAQs – Go Comments

❓ Can Go comments be nested?
✅ No. Multi-line comments (/* ... */) cannot be nested in Go.

❓ What is the godoc tool used for?
✅ It generates documentation from Go source code, using comments written above declarations.

❓ Are comments compiled into the binary?
✅ No. Comments are stripped out during compilation and have no effect on the executable.

❓ Should I comment every line of Go code?
✅ No. Only comment code that isn’t self-explanatory or needs clarification for future maintainers.

❓ Can I use comments to temporarily disable code?
✅ Yes. Use // or block comments to comment out lines of code during debugging or testing.

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