Download - 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
Hong Kong Baptist University
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!
), andThe instruction terminator (;)
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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
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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
. . . .
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-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 =
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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 %
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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
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Changing Type in PHP
s ng se ype settype ( variable_name, data_type);
. . ,
E.g.
$tonydata = 100.00;
$newdata = (string) $tonydata;
variable
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Flow Control - ifStatement
{
// code to excute if the expression evaluates to true
}
elseif (expression)
// code to excute if the previous expression failed and
// this one evaluates to true
}
else
// code to excute in all other cases
}
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Flow control - switch Statement
{
case result1 :
// excute if expression results in results 1break;
// excute if expression results in results 2
break;
default :
// execute this if no break statement
// has been encountered hitherto
}
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? Operator
(expression)?returned_if_expression_is_true:returned_if_expression_ s_ a se;
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Flow control - while, do while
{
}
do
{
// code to be excuted
}
while (expression);
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or a emen
for (variable assignment; test expression; variable increment)
{
}
using continue to skip the iteration
For ($a=0; $a