PHP function variable scope and function return value tutorial

In PHP, regarding variables defined in a function, variables outside the function, including parameters, cannot be accessed, and by default, variables defined outside a function cannot access function variables.

Look at the example below, The code is as follows:

$a = 1;

$b = 2;

function Sum()

{

global $a, $b;

$b = $a + $ b;

}

Sum();

echo $b;

?>

The value of $b returned is 3. In php, global is a global variable, so this is the case, so let’s do it now Look at the php variable reference example, the code is as follows:

function str_unite (&$string)

{

  $string .= 'Also like blue.';

}

$str = ' Like red, ';

str_unite ($str);

echo $str; // Output result: 'Like red, also like blue.'

?>

The above is about the scope of the function References to global variables and functions. Let’s look at the local variables of a function. The code is as follows:

$a = 1;

$b = 2;

function Sum($a,$b)

{//Open source code phpfensi.com

$b = $a + $b;

echo $b;//3

}

Sum();//

echo $b;/ /2

?>