<?php require_once 'product/functions/calculate.php'; require_once 'sum/functions/calculate.php'; echo \product\functions\calculate(3, 2), PHP_EOL; echo \sum\functions\calculate(3, 2); var_dump();
<?php use function product\functions\calculateCircleArea; require_once 'product/functions/calculate.php'; require_once 'sum/functions/calculate.php'; $a = 5; $b = 3; echo \product\functions\calculate($a, $b), PHP_EOL; echo \sum\functions\calculate($a, $b); var_dump(calculateCircleArea(4));