This is my first php program!

20
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Chapter 2: Language Basics
C++ comments
When PHP encounters two slash characters (
//
) within the code, everything from the
slashes to the end of the line or the end of the section of code, whichever comes first,
is considered a comment. This method of commenting is derived from C++. The
result is the same as the shell comment style.
Here are the shell-style comment examples, rewritten to use C++ comments:
////////////////////////
// Cookie functions
////////////////////////
if ($double_check) {
// create an HTML form requesting that the user confirm the action
echo confirmation_form( );
}
$value = $p * exp($r * $t); // calculate compounded interest
Then another
Then another 4
C comments
While shell- and C++-style comments are useful for annotating code or making short
notes, longer comments require a different style. As such, PHP supports block com-
ments, whose syntax comes from the C programming language. When PHP encoun-
ters a slash followed by an asterisk (
/*
), everything after that until it encounters an
asterisk followed by a slash (
*/
) is considered a comment. This kind of comment,
unlike those shown earlier, can span multiple lines.
Here’s an example of a C-style multiline comment:
/* In this section, we take a bunch of variables and
assign numbers to them. There is no real reason to
do this, we're just having fun.
*/
$a = 1; $b = 2; $c = 3; $d = 4;
Because C-style comments have specific start and end markers, you can tightly inte-
grate them with code. This tends to make your code harder to read, though, so it is
frowned upon:
/* These comments can be mixed with code too,
see? */ $e = 5; /* This works just fine. */
C-style comments, unlike the other types, continue past end markers. For example:
$l = 12;
$m = 13;
/* A comment begins here
?>
Some stuff you want to be HTML.
,ch02.15294 Page 20 Wednesday, March 13, 2002 11:42 AM

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