So,
comment is an optional part of a program.
It means that a ready program will work according to its code irrespective of whether there are comments in it or not. However,
comments facilitate understanding of the program code very much.
There are one-line and multi-line comments.
A one-line comment is any sequence of characters following a double slash (//) on the same line.
The sign of a one-line comment is ended by line feed.
A multi-line comment starts with the characters of /* and is ended by */ (see Figure 3).