C++ Comments

In the C++ programming language, comments are lines of code or text that the compiler ignores and does not execute. The main use of the C++ comments is:

• To document the code and improve code readability. The comments also help other programmers to read and understand your code.
• You can comment the code, preventing execution of the code written in comments.

There are two ways of writing comments in C++ language.

1. Single Line Comments
2. Multi-line Comments

Single Line Comment

Any text after // on a single line will be ignored and not executed by C++ compiler.

This is an example of single line comment before line of code to explain the code.

// Declare x, and assign value of 2
int x = 2;

This is another example of single line comment at the end of line of code to explain the code. In this case C++ compiler will ignore the text after the //.

int x  = 2;  // Declare variable x, and assign value of 2
x + 1;  // Add value of 1 to x

Following line of code will be ignored by C++ compiler, and from execution as well.

//int x = 2; 

Multi-line Comments

Multi-line comments in the code are delimited by /* and */ characters. These multi-line comments can span over multiple lines.  The multi-line comments may not be nested.

This example creates a multi-line comments to explain the following code.

/* This line calls the
   function myFunc()
*/
myFunc();

You can also use multi-line comment to prevent execution of block of code.

/*
  int x = 5
  x + 1;
*/