to Global Variables inside functions - php

Question

I have problem to Global Variables inside functions
<?php
function main(){
$var = "My Variable";
function sub() {
GLOBAL $var;
echo $var; // Will show "My Variable"
}
sub();
echo $var; // Will show "My Variable"
}
main();
sub(); // Will not show and I will sub() cant use outside main() function
?>
I just want to global $var inside sub functions
sub() will not work outside main() function
I tied to use GLOBAL but it show nothing ... Any ?

Answer 1

Not sure if i understand what you want, but your $var is not global. its a local variable inside main()
a variable is only global, if you declare it outside of a function or class.
<?php
$var = "My Variable"; // made $var global
function main(){
//removed $var here
function sub() {
global $var;
echo $var; // Will show "My Variable"
}
sub();
echo $var; // Will throw notice: Undefined variable: var
}
main();
sub(); // Will show "My Variable"
?>
why would you declare a method inside a method to call it from there?
maybe something like this is what you want...
<?php
//$var = "My Variable";
function main(){
$var = "My Variable";
$sub = function($var) {
echo "sub: ".$var; // Will show "sub: My Variable"
};
$sub($var);
echo "main: ".$var; // Will show "main: My Variable"
}
main();
// sub(); // Will not work
// $sub(); // Will not work
?>

Answer 2

You do not assing a value to the global scope variable $var.
Only main() assigns a value to a variable called $var but only in main()'s scope. And only main()'s echo $var; actually prints the value. Both calls to sub() do not produce output.
try it with
<?php
function main(){
$var = "My Variable";
function sub() {
GLOBAL $var;
echo 'sub: ', $var, "\n";
}
sub();
echo 'main: ', $var, "\n";
}
main();
sub();
the output is
sub:
main: My Variable
sub:
and please have a read of https://en.wikipedia.org/wiki/Dependency_injection ;-)