The first two lines of our empty program are comments, which don't actually do anything. Instead they are used by the programmer to put information into the program which is of use to us humans.

The information I have put gives a title for the program, the name of the programmer and the date it was written. You should always put this information into your programs. The compiler (which converts our C program into instructions the PICmicro can understand) knows that they are comments because they are enclosed in the /* and */ characters:

/* This is another comment */

You can extend your comments over as many lines as you think sensible, the compiler doesn't mind. I wouldn't bother putting my entire life story in a comment, but you can do this. Whenever I am starting a new section, or doing something interesting, I'll put in a comment to explain what is going on.

It is very important that the /* and */ characters are matched exactly otherwise you will find your program will fail to compile. Another fun mistake is to "comment out" a chunk of your program and then wonder why it doesn't work!.

MPLAB X IDE will colour the comments grey when you are editing.