In C++, comments are used to include explanatory notes within the code. They are not executed by the compiler and serve only as documentation for anyone reading or maintaining the code. Comments can be used to explain code logic, describe the purpose of variables or functions, and temporarily disable code.
There are two types of comments in C++:
Single line comments are used to comment out a single line of code or a portion of a line. They start with // and extend to the end of the line.
<#include <iostream>>
using namespace std;
int main() {
int x = 10; // Initialize x with 10
cout << "Value of x: " << x << endl; // Print the value of x
return 0;
}
Multi-line comments are used to comment out multiple lines of code or a block of text. They start with /* and end with */.
/*
This is a multi-line comment.
It can span multiple lines.
*/
<#include <iostream>>
using namespace std;
int main() {
/*
This is a multi-line comment.
It provides a detailed explanation about the following code.
*/
int y = 20;
cout << "Value of y: " << y << endl; // Print the value of y
return 0;
}
• Documentation: Comments help explain the purpose and functionality of code, making it easier for others (or yourself) to understand and maintain.
• Code Annotation: They can annotate complex code sections, clarifying the intent behind specific implementations.
• Code Management: Comments can be used to temporarily disable code for debugging purposes without deleting it.
• Overuse: Excessive commenting can clutter code and make it harder to read. Comments should be concise and meaningful.
• Outdated: Comments that are not updated along with the code can become misleading, so it's essential to keep them synchronized with code changes.
• No Impact on Execution: Comments have no effect on the execution or performance of the code; they are purely for human readability.
• Be Clear and Concise: Write comments that clearly explain the purpose of the code. Avoid redundant comments that state the obvious.
• Update Comments: Ensure that comments are updated when the code changes to prevent confusion.
• Use Comments Wisely: Use comments to explain "why" something is done rather than "what" is done, as the code itself should be clear on the latter.