Calculate the factorial of a number in PHP

Here’s how you can calculate the factorial of a number in PHP using both iterative and recursive approaches:

Iterative Approach:

function factorialIterative($n) {
    $result = 1;
    for ($i = 1; $i <= $n; $i++) {
        $result *= $i;
    }
    return $result;
}

$number = 5; // Change this to the desired number
$factorial = factorialIterative($number);
echo "Factorial of $number is $factorial";

Recursive Approach:

function factorialRecursive($n) {
    if ($n <= 1) {
        return 1;
    } else {
        return $n * factorialRecursive($n - 1);
    }
}

$number = 5; // Change this to the desired number
$factorial = factorialRecursive($number);
echo "Factorial of $number is $factorial";

Both approaches will give you the factorial of the specified number. The iterative approach uses a loop to calculate the factorial, while the recursive approach uses a function that calls itself to calculate the factorial. Keep in mind that the recursive approach might lead to stack overflow errors for very large numbers due to excessive function calls.