C Comments for code readability and documentation
Writing clear, intelligible, and maintainable C programs requires the use of comments. These are text passages that are directly included in the source code but that the compiler ignores. They are only there to document the program and make it easier for people to read the code, whether that person is the original coder or another developer.
There are two main comment styles that C supports:
Multiline Comments (/* … */): This is how C comments are traditionally written.
- The characters /* are used to start a comment.
- The characters */ mark the conclusion of it.
- Line breaks and everything else between the beginning /* and the closing // are regarded as being a part of the comment. It is hence appropriate for multi-line comments.
- Comment blocks at the start of a program or function are frequently written in this style to include general information such as the file name, author, date, and purpose.
- The inability to nest comments is a major drawback of this design. The first / that appears will prematurely end the outer comment, resulting in syntax issues, if you attempt to comment out a block of code that already contains /… */ comments using this style.
Single-Line Comments (//): After being first used in C++, this style was later incorporated into the C standard (more precisely, C99).
- The characters // are used to start a comment.
- Until the end of the line, any content that comes after these characters is considered a comment.
- For brief inline comments that clarify a single line or a small collection of remarks, this approach works especially well.
- // comments do not have the nesting issue of /*… */ comments because they end at the end of the line. They are therefore helpful for momentarily commenting out single lines or brief code segments that may contain /*… */ comments.
Why are Comments Important?
Comments fulfil a number of vital purposes:
Documentation: They describe the actions of the program, its functions, or particular code blocks. This is essential for anyone attempting to comprehend the code, including you in the future. A program with thoughtful commentary is highly regarded.
Readability: Code can be better organised with comments, which also make difficult reasoning easier to understand. While meaningful variable/function names and appropriate formatting are essential for readability, comments enhance this by offering background information and clarifications.
Maintenance and Debugging: By outlining the original idea and logic, comments can save a great deal of effort when you go back to code you created earlier or when someone else has to edit or correct your code. During debugging, they can also assist in identifying the cause of faults.
Collaboration: Clear comments are practically necessary in team settings so that other members may comprehend and work with the code.
Organizing Thoughts: Clarifying your own reasoning both before and throughout the coding process can be achieved by using comments.
Instead of adding comments as a last step, it is usually advised to write them concurrently with the code. This guarantees that the comments are truly helpful during the debugging stage and that the reasoning is current. Even while they are crucial, too many comments can occasionally make a piece harder to read. The intention is to provide just enough information for the reader to understand.
The basic structure of a basic C program such as “Hello, World!” was covered earlier. The #include directive, the main function, and the printf statement may all be explained using comments, even in that simple example, as shown in the source materials.
This straightforward C program illustrates both comment styles:
/*
* This is a multi-line comment block.
* It typically provides an overview of the file
* or the program's purpose.
* Author: Your Name
* Date: YYYY-MM-DD
*/
#include <stdio.h> // Include the standard input/output library
int main(void) // The main function where program execution begins
{
// This is a single-line comment explaining the next statement
printf("Hello, World!\n"); // printf is used to display output
// \n is the newline character
/* This comment explains the return value.
Returning 0 typically indicates successful execution. */
return 0; // Exit the main function and return 0
}A general description is given in this example by the /*… */ comment block at the top. The #include directive and the printf line’s purpose are explained inline using the // comments. Before the return statement, another /*… */ remark is inserted to clarify its meaning. When the compiler converts the source code into machine code, it ignores both kinds of comments. They serve only the programmer’s interests. Anywhere a blank area is permitted in a C program, comments can be included.