php static variables knowledge

test1.php

<?php
$a = 5;
function test() {
    static $a = 0;
    return ++$a;
}

echo test();
echo test();
echo test();
exit;

Results: 123

test2.php

<?php
$a = 5;
function test() {
    static $a = 0;
    return ++$a;
}

echo test();
echo test();
echo test();
exit;

Results: 111

Reproduced in: https: //www.jianshu.com/p/2446642e4811