PHP function variable scope and function return value tutorial

In the PHP tutorial, the variables defined in a function, including parameters, cannot be accessed by the function external variables, and, by default, variables that are defined outside a function cannot be accessed by the function variables.

Look at the example below

<?php
$a = 1;
$b = 2;
function Sum ()
{
Global $a, $b;
$b = $a + $b;
}
Sum ();
Echo $b;
?> This returns the bits value of 3, in PHP, Global is a global variable all of this, then we look at the PHP variable reference instance

<?php
Function Str_unite (& $string)
{
$string. = ' also like blue. '
}
$str = ' Like Red, '
Str_unite ($STR);
Echo $str; Output: ' Like red, also like blue. '
?>
, which is a reference to the global variable and function of the function's scope, here's a local variable for the function

<?php
$a = 1;
$b = 2;
function Sum ($a, $b)
{
$b = $a + $b;

echo $b;//3
}
Sum ();
Echo $b; executes
?>
This site original tutorial reproduced annotated source www.jzread.com/