formula for factoria; code example

Example 1: factorial

unsigned long long factorial(unsigned long long num){

    if(num<=0)
        return 1;

    return num * factorial(num-1);
}

Example 2: factorial of 8

function getFactorial($int)
{
   
    $factorial = 1;
    for ($i = $int; $i > 1; $i--)
    {
        $factorial *= $i;
    }
    echo "The factorial of " . $int . " is " . $factorial . '<br>';
}