PHP - Chapter 3 - Using Comments


It is always good practice to comment your program or script. This is so anyone who uses your code can easily figure out what a function is doing or why you chose a particular method for doing something. It's also so you will know what your thoughts were if you ever need to revisit a particular script.

There are three ways to make a comment in PHP. The in-line (also called single-line) comment is led by double slashes (//). A multi-line comment is stored in between a C-style comment marker (/* ... */). These two are the most popular ways to specify a comment. A lesser known and lesser used comment marker is the shell style comment marker (#). This is also a single line comment marker.

Type or copy the code below into a text editor, save the file as "script03.php", and upload it to your server.

Definitions (in layman's terms)

Comment: Textual information that is not interpreted by the computer, but is in place for human readability

	<title>Comments in PHP</title>
		echo("<p>Testing in-line comments:</p>");
			// This is an in-line comment

		echo("<p>Testing multi-line comments:</p>");
			/* This is a multi-line, C-Style comment.
			   it can span over more than one line.*/

		echo("<p>Testing shell-style comments:</p>");
			# This is a shell-style comment line

As you can see, the comments aren't interpreted by the computer. They aren't displayed in the browser, nor are they present in the XHTML source.

It is always a good idea to document your code, comments are a good way to do this. Another use for comments is temporarily disabling lines of code for debugging purposes.

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