Comments in C++

Comments are notes written in your code to explain what it does. They are ignored by the compiler and serve purely for human readers — including your future self.

Writing clear comments helps make your code easier to understand, debug, and maintain. C++ supports two types of comments:

• Single-line comments
• Multi-line comments

Single-line Comments

Single-line comments begin with //. Everything after // on that line is ignored by the compiler.

#include <iostream>
 
int main() {
    // This is a single-line comment
    std::cout << "Single-line comment example" << std::endl;
    return 0;
}

✅ When to Use:

• To explain a single line of code
• To temporarily disable a line of code during debugging

Multi-line Comments

Multi-line comments start with /* and end with */. They can span multiple lines and are useful for longer explanations.

#include <iostream>
 
int main() {
    /* This is a multi-line comment.
       It spans across multiple lines.
       Useful for detailed explanations. */
    std::cout << "Multi-line comment example" << std::endl;
    return 0;
}

✅ When to Use:

• To describe a section of code
• For documentation-style comments at the top of files or functions

⚠️ Best Practices

• Avoid over-commenting obvious code. For example:

  int x = 5; // declare an integer and assign 5 ← ❌ too obvious

• Write meaningful comments that explain why something is done, not just what is being done.

• Keep comments up-to-date as code changes.

✅ Summary

Writing clean and helpful comments is a sign of professional programming. As your projects grow, good comments will save you and your teammates a lot of time and confusion.