Comments in C++

Comments help the human readers of our programs. They are typically used to summarize an algorithm, identify the purpose of a variable, or clarify an otherwise obscure segment of code. Comments do not increase the size of the executable program. The compiler ignores all comments.

Example

#include <iostream>
#include <stdlib.h>
int main()
{
    /* This is a 
       multiline comment */
    std::cout<<"Hello World"; // A Single Line Commet
    
    getchar();
    return 0;
}

A comment pair can be placed anywhere a tab, space, or newline is permitted. Comment pairs can span multiple lines of a program but are not required to do so. When a comment pair does span multiple lines, it is often a good idea to indicate visually that the inner lines are part of a multi-line comment. Our style is to begin each line in the comment with an asterisk, thus indicating that the entire range is part of a multi-line comment.
 
Programs typically contain a mixture of both comment forms. Comment pairs generally are used for multi-line explanations, whereas double slash comments tend to be used for half-line and single-line remarks.
 
Too many comments intermixed with the program code can obscure the code. It is usually best to place a comment block above the code it explains.
 
Comments should be kept up to date as the code itself changes. Programmers expect comments to remain accurate and so believe them, even when other forms of system documentation are known to be out of date. An incorrect comment is worse than no comment at all because it may mislead a subsequent reader.
 
Comment Pairs Do Not Nest
 
A comment that begins with /* always ends with the next */. As a result, one comment pair cannot occur within another. The compiler error message(s) that result from this kind of program mistake can be mysterious and confusing.