Comments in C++

Program comments are explanatory statements that you can include in the C++ code that you write and helps anyone reading it's source code. All programming languages allow for some form of comments.
C++ supports single-line and multi-line comments. All characters available inside any comment are ignored by C++ compiler.

C++ comments start with /* and end with */. For example:

/* This is a comment */

/* C++ comments can  also
 * span multiple lines
 */

A comment can also start with //, extending to the end of the line. For example:

#include <iostream>
using namespace std;

main() {
   cout << "Hello World"; // prints Hello World

   return 0;
}

When the above code is compiled, it will ignore // prints Hello World and final executable will produce the following result:

Hello World

Within a /* and */ comment, // characters have no special meaning. Within a // comment, /* and */ have no special meaning. Thus, you can "nest" one kind of comment within the other kind. For example:

/* Comment out printing of Hello World:

cout << "Hello World"; // prints Hello World

*/