ch.6b php basic

8/9/2019 ch.6b php basic

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Hong Kong Baptist University

Week 6

Basic PHP and Program Flow

22/02/2010

Dr. Tony Chun-Kuen WONG

Coordinator, BBA(Hons) Information Systems Management Major

Coordinator, BBA(Hons) Information Systems and e-Business ManagementConcentration

Department of Finance and Decision Sciences

School of Business


PHP Basic

< tm > < tm > are used to inform the web server this is a html program

Just send to client browser to interpret

e ex ens on Filename.htm or Filename.html

First Tag

Second Tag

=

The web server will parsed it using the PHP parser which is the Zend engine in oursystem

File extension Filename.php or Filename.php3 or Filename.php4

First example phptags.php http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/phptags.php


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PHP Basic

Second Example

Combining HTML and PHPfirstscri t. h

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/firstscript.php

Both tab and PHP tag exist in the same programw t extens on .p p

Program note Command (Echo)

The String (

Hello World! Im using PHP!
), and
The instruction terminator (;)


PHP Basic

Third Examples with error in instruction terminator errorscript-a.php

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/errorscript-a.php

errorscript-b.php http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/errorscript-b.php

Fourth Examples with error in escape (\) charactererrorscript2-a.php

ttp: sem . u.e u. ~ semuser p pexamp es errorscr pt -a.p p

errorscript2-b.phphtt ://isem03.hkbu.edu.hk/~isemuser20/ h exam les/errorscri t2-b. h


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PHP Basic

Commenting your code Insert comments into code

//single line comment

# another single line comment

/*

multiple

line

comment

*/

Fifth Example comments. h

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/comments.php


Variable

, Tony or Cool or 100 or

Example

$username = Tony; $mark= 100;

Use meaningful name such as

$totalmark, $studentname, $brandofcar or

Name you need to guess $p, $benz, $honda,


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Variables and Operators in PHP

Data Type in PHP Standard Type

Integer

Double

String (USING or TO quote the character andusin \ and\ to rint and within the strin

Boolean

Object

Array

Special Data Type Resource (Reference to a third party resources)

NULL (An uninitialized variables)

Sixth example printvarscript.php

. . . .


-http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/phpinfo.php

$_GET Contains variables with get method

$_POST Contains variables with put method

$_COOKIE Contains variables through cookies

$_FILES Contains variables through file upload

_

Contains variables about server environment

SESSION_ Contains variables registered in a session


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Constants

A constant is an identifier for a value that cannot

chan e durin the course of a scri t

_ ,

E.g. define (TONY_CONST, 114);

Remark

in definition)

E.g. define (TONY_CONST, 114 , true);

Then Tony_Const = TONY_CONST =


Constants

Seventh example constants.php

p: sem . u.e u. ~ semuser p pexamp es cons an s.p p

Some redefined constants _FILE_ ; _LINE_ ; PHP_VERSION ; PHP_OS

ghth examp e constants2.php

~. . . .


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Assignment and Arithmetic operators

ss gnmen =

Arithmetic on

Substraction -

Multi lication *

Division /

Modulus %


operators

Concatenation .

E.g. hello . world return helloworld Combined Assignment

+= , -= , *= ,/= , %= , .=

E.g. $x *= 5 is equivalent to $x = $x * 5;


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Comparsion Operators

== equ va en

!= non-equivalent === ent ca same ata type

>

>=

== === !=

&&

||

* - .

and

xor

or


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Operators examples

ass gnscr p .p p

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/assignscript.php

arithmeticscript.php

htt ://isem03.hkbu.edu.hk/~isemuser20/ h exam les/arithmeticscri t. h

comparisonscript.php

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/comparisonscript.php

logicalscript.php

http://isem03.hkbu.edu.hk/~isemuser20/phpexamples/logicalscript.php


Changing Type in PHP

s ng se ype settype ( variable_name, data_type);

. . ,

E.g.

$tonydata = 100.00;

$newdata = (string) $tonydata;

variable


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Flow Control - ifStatement

{

// code to excute if the expression evaluates to true

}

elseif (expression)

// code to excute if the previous expression failed and

// this one evaluates to true

}

else

// code to excute in all other cases

}


Flow control - switch Statement

{

case result1 :

// excute if expression results in results 1break;

// excute if expression results in results 2

break;

default :

// execute this if no break statement

// has been encountered hitherto

}


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? Operator

(expression)?returned_if_expression_is_true:returned_if_expression_ s_ a se;


Flow control - while, do while

{

}

do

{

// code to be excuted

}

while (expression);


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or a emen

for (variable assignment; test expression; variable increment)

{

}

using continue to skip the iteration

For ($a=0; $a

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