The factorial is a function of a non-negative integer , whose output is a pruduct of all positive integers less or equal than
. The factorial of 0 is defined as 1.
The factorial of a number is denoted as
.
Examples
Code
/**
* Returns the factorial of a number n using iteration
* @param number number n >= 0
* @return the factorial of a number n
*/
public static int factorial(int number) {
if (number < 0) throw new IllegalArgumentException("Negative argument");
int result = 1;
for (int i = number; i > 1; i--) {
result *= i;
}
return result;
}
/**
* Returns the factorial of a number n using recursion
* @param number number n >= 0
* @return the factorial of a number n
*/
public static int factorialRec(int number) {
if (number < 0) throw new IllegalArgumentException("Negative argument");
if (number == 0 || number == 1) return 1;
return number * factorialRec(number - 1);
}
/**
* Returns the factorial of a number n using iteration
* @param number number n >= 0
* @return the factorial of a number n
* @author Thomas (www.adamjak.net)
*/
int fakt(int number) {
if (number < 0)
{
return 0;
}
int i, result = 1;
for (i = number; i > 1; i--)
{
result *= i;
}
return result;
}
/**
* Returns the factorial of a number n using recursion
* @param number number n >= 0
* @return the factorial of a number n
* @author Thomas (www.adamjak.net)
*/
int fakt_rek(int number) {
if (number < 0)
{
return 0;
}
if (number == 0 || number == 1)
{
return 1;
}
return number * fakt_rek(number - 1);
}
/**
* Calculates the factorial of a number n using iteration
* @param $number number n >= 0
* @return the factorial of a number n
* @author Thomas (www.adamjak.net)
*/
function factorial($number) {
if ($number < 0) {
die("Negative argument");
}
$result = 1;
for ($i = $number; $i > 1; $i--) {
$result *= $i;
}
return $result;
}
/**
* Calculates the factorial of a number n using recursion
* @param $number number n >= 0
* @return the factorial of a number n
* @author Thomas (www.adamjak.net)
*/
function factorial_rec($number) {
if ($number < 0) {
die("Negative argument");
}
if ($number == 0 || $number == 1) {
return 1;
}
return $number * factorial_rec($number - 1);
}
fact(0,1). fact(N,R) :- N >= 0, integer(N), N1 is N - 1, fact(N1,R1), R is N * R1.
(defun fact (x) "generates factorial of x" (if (= x 0) 1 (* x (fact (- x 1))))) (defun fact2 (x) "generates factorial of x" (if (zerop x) 1 (* x (fact2 (1- x))))) (defun fact3 (x) "generates factorial of x" (cond ((zerop x) 1) (T (* x (fact3 (1- x))))))