What is Factorial?
The factorial of a positive integer n, denoted by n!, is the product of all positive integers less than or equal to n.
n! = n * (n - 1) * (n - 2) * (n - 3) ... 3 * 2 * 1
Example
The factorial of 0! is 1 The factorial of 5! is 5 * 4 * 3 * 2 * 1 = 120.
Write a function to calculate factorial of n using iteration.
Java
public class FactorialRecursion {
public static void main(String[] args) {
System.out.println(factorial(0) == 1);
System.out.println(factorial(1) == 1);
System.out.println(factorial(2) == 2);
System.out.println(factorial(3) == 6);
}
public static long factorial(int n) {
return n == 0 || n == 1 ? 1 : n * factorial(n - 1);
}
}