Question

How to calculate factorial of a number using recursion in PHP

Answer 1

$n = 5;
   
printf("Factorial of %d is: %ld\n", $n, recursiveFactorial($n));
 
function recursiveFactorial($n)
{
  if ($n == 0)
    return 1;
  else
    return($n * recursiveFactorial($n - 1));
}

/*
run:

Factorial of 5 is: 120

*/

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Answer 2

function factorial($n)
{
  if($n < 1) $n = 1;
  
  return array_product( range(1, $n) );
} 

echo factorial(5)


/*
run:

120
 
*/

 

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Answer 3

function factorial( $n )
{
  if($n < 1) $n = 1;
  
  $fact = 1;
 
  for ($i = 2; $i <= $n; $i++)
        $fact = $fact * $i;
 
  return $fact;
} 

echo factorial(5)


/*
run:

120
 
*/

 

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