19. Variable Scope: Local, Global, and Static

Variable scope determines where a variable can be accessed, read, and modified within a script.

1. Local Scope

Variables declared inside a function are local to that function and cannot be accessed from outside.

php

"; } testScope(); // echo $local_var; // ERROR: Undefined variable ?>

2. Global Scope

Variables declared outside any function have global scope. They can be accessed globally, but not directly inside functions.

To access a global variable inside a function, you must use the global keyword or the special $GLOBALS array.

php

"; // Method B: using the $GLOBALS superglobal array $GLOBALS['global_message'] = "I was modified in the function."; echo "Global using GLOBALS: " . $GLOBALS['global_message'] . "
"; } accessGlobal(); echo "Outside function after modification: " . $global_message; ?>

3. Static Scope

Variables declared with the static keyword inside a function retain their last value between multiple calls to that function, instead of being destroyed after the function finishes.

php

"; } counter(); // 1 counter(); // 2 counter(); // 3 ?>