C++ Comments

In this tutorial, we will learn about C++ comments, why we use them, and how to use them with the help of examples.

C++ comments are hints that a programmer can add to make their code easier to read and understand. They are completely ignored by C++ compilers. They are added with the purpose of making the source code easier to read for the people who are from non-coding background.

There are two ways to add comments to code:

// - Single Line Comments
/* */ - Multi-line Comments

Single Line Comments

In C++, any line that starts with // is a comment. For example,

// declaring a variable
int x;

// initializing the variable 'x' with the value 5
x = 5;

Here, we have used two single-line comments:

// declaring a variable
// initializing the variable 'x' with the value 5

We can also use single line comment like this:

int x; // declaring a variable

Multi-line comments

In C++, any line between /* and */ is also a comment. For example,

/* declaring a variable
to store salary to employees
*/
int sal = 5000;

This syntax can be used to write both single-line and multi-line comments.

Using Comments for Debugging

Comments can also be used to disable code to prevent it from being executed. For example,

#include <iostream>

using namespace std;

int main() {
    cout 
            If we get an error while running the program, instead of removing the errorprone
                code, we can use comments to disable it from being executed; this
                can be a valuable debugging tool and save time to delete the wrong code
                and to rewrite it.
            #include <iostream>

using namespace std;

int main() {
    cout 
            Pro tip: Remember the shortcut for using comments; it can be really
                helpful. For most code editors, it's Ctrl + / for Windows and Cmd + / for
                Mac.
            Why use Comments?
            If we write comments on our code, it will be easier for us to understand the
                code in the future. Also, it will be easier for your fellow developers to
                understand the code.
            Note: Comments shouldn't be the substitute for a way to explain poorly
                written code in English. We should always write well-structured and selfexplanatory
                code. And, then use comments.
            As a general rule of thumb, use comments to explain Why you did
                something rather than How you did something, and you are good.