1. PHP Intro/Overview
Bird Book pages 1-11,

2. Server-side Scripting
Everything you need to know in one slide
Web server (with PHP “plug-in”) gets a URL
Web server see’s that the page is .php
PHP Pre-processor searches the page for PHP code and executes the code.
Web server sends back the output of the PHP code, not the code itself.

3. PHP Basics
PHP code can go anywhere in an HTML document as long as its in a PHP tag
Example
<h1><?php echo “Hello World”; ?></h1>

4. PHP Variables Variables do NOT have strict typing
Unless math operations are used, variables are strings by default
Variables must start with $
<?php
$x = “Hello World”;
echo $x;
?>

5. Commenting
3 Types
// Comment
# Comment
/* Comment
Comment */

6. Print and Echo Print can print strings print “42”;
Echo is more robust than print, it can print numbers and more than one parameter, separated by commas
echo 42; // This will actually print 42
$x = “is”
echo “The answer ”, $x, “ ”, 42;

7. Single Quotes vs. Double
These are the same…
print “This works.”;
print ‘This works also.’;
This makes it easy to print quotes
print “Here is a ‘single quote’ ”;
print ‘Here is a “double quote” ’;

8. New lines
The string variable $var contains a new line character  “Hello there\n sir!”
$var = “Hello there
sir!”;
Introducing new lines breaks makes it easer to write SQL queries that work…

9. SQL Example $query = “ SELECT max(orderid) FROM orders
WHERE custid = $ID”;
If you send this query string to some database server it is important that the new line characters are in the string.

10. Variables in strings $x = 256 // “My computer has 256 MB ram.”
$message = “My computer has $x MB ram.”;
// “My computer has.”
$message = “My computer has $xMB ram.”;
Why?

11. Variables in strings $x = 256 // “My computer has.”
$message = “My computer has $xMB ram.”;
// “My computer has 256MB ram.”
$message = “My computer has {$x}MB ram.”;

12. Variables in strings
Using { } is very important when trying to include complex variables into other strings.
$message = “Mars has a diameter of {$planets[‘Mars’][‘dia’]}.”;

13. Variables Integers $var1 = 10; Floats $var2 = 6.1; Boolean
$var3 = true;
String
$var4 = “true”;
$var5 = ‘true’;
$var6 = ‘10’;
$var7 = “6.1”;

14. Constants define(“PI”, 3.14159); print PI; // outputs 3.14159
Notice that constants don’t have $
Convention: Use all CAPS for constants
BTW, PHP is case sensitive

15. Expression and Operators
Same as most high-level languages
$z = 3;
$x = 1;
$y = 5.3;
$z = $x + $y;
$z++;
$x += $y + 10;
$z = $x * 10;

16. String concatenation Not the same as JavaScript! $var1 = “Hello”;
$var2 = “ world”;
$var3 = $var1 + $var2; //This won’t work
$var3 = $var1 . $var2;

17. Conditionals (if statements)
Same as other high-level languages
if ($var < 5) {
print “The variable is less than 5”; }

18. Compound conditionals
if ($x == 1) {
print “x is 1”; }
elseif ($x == 2) { //  Notice elseif is one word
print “x is 2”;
else {
print “x is not 1 and not 2”;

19. Loops While $c = 0; while ($c < 10) { print $c . “ ”; $c++; } For
for ($c = 0; $c < 10; $c++) {
print $c . “ ”; }

20. Loops: break for ($c = 0; $c < 10; $c++) { print $c . “ ”;
if ($c == 5)
break; }

21. Type Conversion $year = 2003; // This is an integer
$yearString = strval($year);
// $yearString is “2003” not an integer

22. Type Conversion string strval(any other datatype)
integer intval(any other datatype)
float floatval(any other datatype)

23. Implicit type conversion
$var = “100” + 15;
$var = ;
$var = 39 . “ Steps”;
$var = 39 + “ Steps”;

24. Implicit type conversion
$var = “100” + 15; // $var becomes int
$var = ; // $var becomes float
$var = 39 . “ Steps”; // $var becomes string
$var = 39 + “ Steps”; // $var become int

25. Functions // Function definition
function fname ($parameter1, $parameter2) {
code; …
return $returnvalue; }
// Function call
$x = fname(1,2);

26. Variable Scope (visibility)
Same as Java
Same as C++
function fun($x) {
$temp = $x + 1; }
fun(5);
print “temp is: $temp”;