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Introduction to PHP

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PHP

Server-side scripting language useful for writing CGI

Began as online tools by Rasmus erfdorf! PHP " Personal Home Page tools

! Bottom-up development# $as become e%tremely popular today Somew$at li&e C but muc$ $ig$er level# ''P model was added later

(specially wit$ )pac$e*inu%*+yS,

Runs on bot$ ni% and .indows platforms# wit$ most web servers

sed today wit$ many commercial sites

)vailable for free! $ttp/**www0p$p0net

! 1ocumentation and many resources available online I prefer t$e online documentation# easy to searc$ 2several +b as a

single large H3+ file4

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Simple PHP Script

Consider t$e following H3+ file# e%ample0$tml/

5$tml6

5$ead6

5title6+y Page5*title6

5*$ead6

5body6

5p6Hello world75*p6

5*body6

5*$tml6

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Simple PHP Script

Here is an e8uivalent PHP script0 PHP files $ave t$e e%tension 90p$p: and maycontain bot$ H3+ and PHP code# w$ic$ is enclosed inside 5;p$p code ;6tags# or alternately 5; code ;6 2if supported4

5$tml6

5$ead6

5title6+y Page5*title65*$ead6

5body6

5;p$p

print295p6$ello world75*p6:4 or t$e empty string 9:

Common novice mista&e/ Oorgetting t$e J

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ariables

Interpreted< consider t$e following/

J% " =

! (%/

Jarr>U " 9$ello:>>>

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In$eritance

'perates li&e you would e%pectclass foo

public function printItem2Jstring4

ec$o TOoo/ T 0 Jstring 0 T5P6Tname . "\n"; }

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)bstract Classes

)bstract classes cannot be instantiated< abstract met$ods cannot be

implemented in a subclass

abstract class )bstractClass

** Oorce (%tending class to define t$is met$od

abstract protected function getalue24