The "look and feel" of PHP

As stated before, PHP code goes right in your html document, and is executed by the web server module. Here's an example:

		<HTML>
			<HEAD><TITLE>What time is it?</TITLE></HEAD>
			<BODY>

			The time is now 
			<?php 
				print(date("d/m/Y H:i:s",time())); 
			?>
			</BODY>
		</HTML>

When this page viewed, the body would look something like:

		The time is now 10/02/2001 20:06:07

If you simply want to print out the contents of a value, and your php.ini file is configured for it, you can use:

		The time is now <?=date("d/m/Y H:i:s",time())?>

The <?php and ?> tags do not have to be on the same line.

One hard concept to grasp is that the <?php ?> tags are merely to delimit what is PHP code and what is HTML. The whole page is processed by the PHP module. So different parts of the same program can be in different <?php ?> tags, and even have HTML between them. So you can do things lile

		Authorizing... You are 
		<?php if(Authorized($UserName)) {  ?>
		authorized.  Please proceed.
		<?php }  else { ?>
		<FONT COLOR="RED" SIZE="+2"> NOT AUTHORIZED! A security team has been dispatched.  Please remain where you are.
		<?php } ?>

This also means variables with global scope (declared outside of functions) have page scope, and can be referenced from different blocks of PHP code on that page.

Why PHP is like C/C++

More things look like function calls than in Perl.
Classes, subclasses, methods, and initializers look and work much like they do in C++
Variables can be casted to other datatypes
A variable can be a reference for another variable as in
```
			$bar = &$foo;
		
```
A parent's globals are not explicitly visible to functions it calls.
The scope of a variable is the context within which it is defined.
you can put the name of a function in a string variable, and execute the function by simply naming the string, which can be used where you would use a pointer to a function in C. for example
```
			$string = "date"; 
			$t = $string("YMH"); 
		
```
PHP has a switch statement

Why PHP is like Perl

Variables are loosely typed, and often change as needed automaticaly. Integers (2^32), floats, strings, arrays (associative, indexed, and multidimensional), and objects are supported.
PHP almost always passes arguments by value and not by reference.

Variables can be used in variable names as in

			$a = "hello";
			$$a = "world";              # Same as $hello = "world"
			print("$a ${$a}");			# prints "hello world"

You can run external commands by putting them in backquotes (among other methods).

PHP 4 (not PHP 3) includes a foreach and an each construct, much like perl and some other languages. Like:

			foreach(array_expression as $value) statement
			foreach(array_expression as $key => $value) statement

Function definitions are similar to Perl

			function Add ($arg_1, $arg_2) 
			{
				return $arg_1+$arg_2;
			}

PHP has include() and require() constructs that work as they do in Perl, not like #include in C.
Functions can return a list containing multiple values.

Why PHP is unique

The environment variables Apache sets, as well as submitted form fields, are automatically instantiated as variables.
Any expression that may fail upon evaluation can be prefaced with an @ symbol to ignore failures.
Function names are case-insensitive.