0304.php

<?php

declare (strict_types = 1);

// This is a regular anonymous fn
// anonymouse fn is when you define fn as variable

$sumNum = function (int $num1, int $num2): int {
    return $num1 + $num2;
};
echo $sumNum(3, 7);

// now if you want to avoide use of `use` keyword & if you want to pass fn as argument then use arrow fn

$multiplyNum = fn(int $num1, int $num2) => $num1 * $num2;

echo $multiplyNum(3, 7);

echo $sumNum(2, $multiplyNum(3, 4));
echo '<br>';

$currentYr = date('Y');

$salaryInc = function (int $current, int $groth) use ($currentYr) {
    return $current + $groth + $currentYr;
};
echo $salaryInc(1000, 500);

$bonusInc = fn(int $current, int $per) => (($current * $per) / 100 + $currentYr);

echo $bonusInc(2000, 5);