Intro To PHP David Lash Getting Started With

Using Comments with PHP Scripts l Comment Syntax - Use // l Can place on Same line as a statement: Note: Comment lines are ignored when the script runs. They do not slow down the run-time 22

Alternative Comment Syntax PHP allows a couple of additional ways to create comments. l Multiple line comments. 23

More on phpinfo() l Use a script with the following to find out about your PHP installation: The php version » This build does NOT have mysql! Location of PHP main config file Other interesting items: Apache version & configuration, php config variables, environment. 24

More on phpinfo() Allow ASP style tages Manual strongly recommends setting to off Flag values indicates which Value constant errors to display/log 1 E_ERROR 2 E_WARNING 4 E_PARSE 8 E_NOTICE 16 E_CORE_ERROR 32 E_CORE_WARNING 64 E_COMPILE_ERROR 128 E_COMPILE_WARNING 256 E_USER_ERROR 512 E_USER_WARNING 1024 E_USER_NOTICE 2047 E_ALL 2048 E_STRICT 25

Error Definitions. . . Value Constant Description Note 1 E_ERROR (integer) Fatal run-time errors. These indicate errors that can not be recovered from, such as a memory allocation problem. Execution of the script is halted. 2 E_WARNING (integer) Run-time warnings (non-fatal errors). Execution of the script is not halted. 4 E_PARSE (integer) Compile-time parse errors. Parse errors should only be generated by the parser. 8 E_NOTICE (integer) Run-time notices. Indicate that the script encountered something that could indicate an error, but could also happen in the normal course of running a script. 16 E_CORE_ERROR (integer) Fatal errors that occur during PHP's initial startup. This is like an E_ERROR, except it is generated by the core of PHP. since PHP 4 32 E_CORE_WARNING (integer) Warnings (non-fatal errors) that occur during PHP's initial startup. This is like an E_WARNING, except it is generated by the core of PHP. since PHP 4 64 E_COMPILE_ERROR (integer) Fatal compile-time errors. This is like an E_ERROR, except it is generated by the Zend Scripting Engine. since PHP 4 128 E_COMPILE_WARNING (integer) Compile-time warnings (non-fatal errors). This is like an E_WARNING, except it is generated by the Zend Scripting Engine. since PHP 4 256 E_USER_ERROR (integer) User-generated error message. This is like an E_ERROR, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4 512 E_USER_WARNING (integer) User-generated warning message. This is like an E_WARNING, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4 1024 E_USER_NOTICE (integer) User-generated notice message. This is like an E_NOTICE, except it is generated in PHP code by using the PHP function trigger_error(). since PHP 4 2047 E_ALL (integer) All errors and warnings, as supported, except of level E_STRICT. 2048 E_STRICT (integer) Run-time notices. Enable to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code. since PHP 26

‘Overriding’ php. ini settings Global is ’ 85’ Local is 2047. 27

Apache 2 triad provide config administrator Show errors in browser Include HTML errors Note: Has option at bottom to save configuration. Also must restart apache for 28 changes to take effect.

Setting Your own Configuration Options 2047 E_ALL (integer) All errors and warnings, as supported, except of level E_STRICT. 2048 E_STRICT (integer) Run-time notices. Enable to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code. since PHP 29

Visit www. php. net Quick function search Function manual 30

Objectives l To understand what PHP is » What is HTML » How PHP compares with CGI l Getting Started with PHP » Your first script » PHP syntax and embedding in HTML » Finding out about your PHP configuration l Using PHP variables » Numerical variables and operators » String variables, operators and a few functions l Separating PHP from HTML using

PHP allows creating variables on the fly l For example, l A PHP variable names must: » Use a dollar sign ($) as the first character » Use a letter or an underscore character (_) as the second character. 32

Combining Variables and the print Statement l Use print statement with double quotes: $age=6; print ("Bryant is $age years old. "); print (‘but george is $age years old. ’); Double quotes output any variable’s value Single quotes output any variable’s name. Would output: Bryant is 6 years old but george is $age years old. 33

Using Arithmetic Operators l l PHP supports various arithmetic operators. For example These PHP statements would output The total number of fruit is 26. 34

Common PHP Numeric Operators 35

Common PHP Combined Assignment Operators 36

A Full Example 1. 2. 3. 4. 37

WARNING: Using Variables with Undefined Values Use a variable without a value assigned will have no value (called a null value). PHP will NOT generate an error and will complete the expression. For example, Will output x= y=4. 38

PHP Precedence Rules l PHP follows the precedence rules listed below. » First it evaluates operators within parentheses. » Next it evaluates multiplication and division » Finally it evaluates addition and subtraction For example, the first 2 statements evaluate to 80 while the last to 180. $x = 100 - 10 * 2; $y = 100 - (10 * 2); $z = (100 - 10) * 2; 39

Objectives l To understand what PHP is » What is HTML » How PHP compares with CGI l Getting Started with PHP » Your first script » PHP syntax and embedding in HTML » Finding out about your PHP configuration l Using PHP variables » Numerical variables and operators » String variables, operators and a few functions l Separating PHP from HTML using

Working with PHP String Variables Use character strings for data such as customer names, addresses, product names, and descriptions. l E. g. , l » $name="Christopher"; » $preference="Milk Shake"; Note: Technically it is more correct to write: $name=‘Christopher’; $preference=‘Milk Shake’; Since there are no variable values to evaluate. 41

WARNING: Be Careful Not to Mix Variable Types l Be careful not to mix string and numeric variable types. No error will occur instead will output: y=1 42

Using the Concatenate Operator The concatenate operator combines two separate string variables into one. l For example, l » $fullname = $firstname. $lastname; will receive the string values of $firstname and $lastname connected together. l For example, l $fullname $firstname = "John"; $lastname = "Smith"; $fullname = $firstname. $lastname; print ("Fullname=$fullname"); 43

TIP: Different ways to concatenate strings. l A couple different ways to concatenate strings: » Concatenation operator l $Fullname 2 = $First. Name. " ". $Last. Name; » Double quotes l $Fullname 2 = "$First. Name $Last. Name"; » Concatenation combination operator l $comment = ‘I love this job’; l $comment. = ‘but the hours and not that good’; » Mix and match: l $name = ‘George’; l $comment = “$name said: I love this job”; l $comment. = ‘but the hours and not that good’; 44

The strtolower() and strtoupper() Functions These functions return the input string in all uppercase or all lowercase letters, respectively. l For example, l Would output “upper=NOW IS THE TIME lower=now is the time”. 45

Objectives l To understand what PHP is » What is HTML » How PHP compares with CGI l Getting Started with PHP » Your first script » PHP syntax and embedding in HTML » Finding out about your PHP configuration l Using PHP variables » Numerical variables and operators » String variables, operators and a few functions l Separating PHP from HTML using

Evaluation delimiters 1 2 3 4 5 6 7 8 9 10 11 12 13 mysite. com '; $store = ' toy store '; $special = 'boxed block sets'; ? > Welcome to the our special today is Visit our home page at Can separate PHP from HTML and use

Getting input data l To receive data with REGISTER_GOBALS OFF you use a special variable called $_GET. » $mynm = $_GET[“name”]; Enclose in square bracket and then quotes Name of HTML form CGI variable (note do not use $) Special PHP Global variable. Technically it is an associative array (covered in chptr 5. ) PHP variable name that you want to receive the HTML form input. 48

Sending Input From URL l You can send data to your application by: » http: //www. indelible-learning. com/php/module 1/input. php? special=Baseball Bats l If needed to send multiple input variables could: » http: //www. indelible-learning. com/php/module 1/input. php? special=Baseball Bats&myname=Dave Use & sign 49

Objectives l To understand what PHP is » What is HTML » How PHP compares with CGI l Getting Started with PHP » Your first script » PHP syntax and embedding in HTML » Finding out about your PHP configuration l Using PHP variables » Numerical variables and operators » String variables, operators and a few functions l Separating PHP from HTML using

Module 1 Hands on Assignment l Create a php script that calculates the total possible revenue of a theater. Suppose that: » » The theater charges $5 per seat The theater has with 10 rows and 8 seats per row. Output the total possible revenue. Set the seat cost, rows and seats per row at top of script and separate PHP from HTML code. 51

One possible solution 1 6 7 8 9 We have seats in the house 10 11 At a costs of $ our total possible revenue is 12 . 13 52

Lab 1 Extension Exercise l Modify that same script to receive the values of $rows and $cols from the Web URL. » Send different input values from the web 53

One Possible Solution We have seats in the house At a costs of $ our total possible revenue is . 54