PHP - FAQS - Frequently Asked Questions

Php is a open source plat form, This blog will help you to learn php concepts by experts.

To install PHP we have some third party tools

EX :

XAMPP
WAMP
Easy PHP
Note :

Our s/w is XAMPP , it includes Apache , My SQL , PHP , Perl for XP

Every server has some root Directory ( where we have to save the programs )

XAMPP - htdocs

WAMP - www

Easy PHP - www
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All web servers are deped on Port 80

We can change the port no in :

XAMPP\apache\conf\httpd.conf

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Create your folder in

C:\xampp\htdocs to save your programs ( ex : satish)

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Ex 1 :

echo 'Welcome';
?>

Save the file in your folder satish ( a.php )

Run the program :

Go to browser

http://localhost/satish

select your program from the list to run it

Note :

1) if you save your PHP program with the name index.php in your folder satish
the the program will automatically run when you are enter http://localhost/satish in the browser

2) instead of giving localhost we can give like this also http://127.0.0.1/satish

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Variable


Variable is a memory location where we can store the values.

Ex 1 :
Var $a;
$a = ‘srihitha’; - Wrong

Ex 2 :
Var $a = ‘srihitha’; - Wrong

Ex 3 :
$a = ‘srihitha’; - correct

Conditions for variable names :

First char of var name must be in A-Z (or) a-z (or) _ (underscore) .
Spaces are not allowed.
Avoid built in functions and reserve words as variable names.
Data Types :

Numaric ( int – 4 bytes , float – 8 bytes )

String ‘abc’ or “abc”

Boolean True or False

Note :

If any char create problem in a string then use \


Ex :
“Hai \” I am satish “

\ indicates to browser that coming char is not a special char.

Ex 1 :

echo "Hai \" I am satish "
?>

Ex 2 :

$a = '10';
$b = 20;
$c = $a + $b;
echo $c;
?>

Note : with using string conversion method it will convert string into integer when u Preformed arithmetic operation

Ex 3 :

$a = '10abc4';
$b = 40;
$c = $a + $b;
echo $c;
?>

Ex 4:

$a = 'abc5';
$b = 10;
$c = $a + $b;
echo $c;
?>

Boolean

Boolean a = true;
Boolean a = false;

Note : don’t put any quotations ( Ex : ‘treue’ )

Ex :

$a = true;
echo $a;
?>

----------------------------------------------------------------

To get the data type of var

Ex 1 :

$a = true;
var_dump($a);
?>

It will display data type and value.

Ex 2 :

$a = 'abc';
var_dump($a);
?>

It will display data type,length and value.

Ex 3 :

$a = 10;
var_dump($a);
?>
It will display data type and value.

Note :

“ “ are used for variable expansion

Ex :

$a = 10;

echo $a;

echo '$a';

echo "$a";
?>

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Concatenation symbol is . or ,

For next line we can use ‘
’

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Ex :


$a = 'abc';
$b = 'xyz';

echo $a.'
';
echo $b;

?>