The static keyword is also used to declare variables

Function which keep their value after the function has ended.

<?php
function add() {
    static $count = 0;
    $count++;
    echo $count;
}

add(); // The Output is : 1
add(); // The Output is : 2
add(); // The Output is : 3

?>

• The static keyword is used to declare the variable $count as static within the add() function.
• The variable is initialized with a value of 0 the first time the function is called.
• $count is retained from the previous call and incremented by 1.