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PHP Variable Scope
Posted on: March 17, 2010 at 12:00 AM
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This PHP tutorial is all about the scope of a variable in PHP. The Variable in PHP has a life in the program and in programming language we call it as the scope means the area in which the value of the variable is applicable.

PHP Variable Scope:

In every language every variable has a scope, may be within a block or within the whole program etc.  Generally the scope of a variable in PHP is inside a function or inside a block. To make the variable global either use global keyword or $GLOBALS array keyword.

Another way of scoping  is static variable,  the scope of a static variable exists only in a local function scope, but the value persists even after the execution of the program.

Scope of Variables in PHP with Example:

<?php

$a=34;

{

echo "Value of \$a inside the block is= ".$a;

$a=45;

echo "Value of \$a inside the block is= ".$a;

}

echo "Value of \$a outside the block is= ".$a;

?>

 

Output:

Value of $a inside the block is= 34
Value of $a inside the block is= 45
Value of $a outside the block is= 45

 

Example:

<?php

$a=4;

add();

function add()

{

$a=34;

global $a;

echo $a + $a;

}

?>

Output:

8

Example:

<?php

function display()

{

$a=23;

echo $a."<br/>";

}

$a="string";

display();

echo $a;

?>

Output:

23
string

Example:

<?php

function display()

{

static $a=-1;

echo $a++."<br/>";

}

display();

display();

?>

Output:

-1
0

Example:

<?php

$a=43;

$b="Hello";

function Disp()

{

echo $GLOBALS['a'];

echo "<br/>".$GLOBALS['b'];

}

Disp();

?>

Output:

43
Hello

 

 

 

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Posted on: March 17, 2010

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