Permutation related algorithm

Question

Good day. I need some help with looking for the NUMBER OF possible permutations using java.

For example, if n = 3 and k = 3 (n for the length of the characters and k for the number of characters you would want to take to permute).

Our formula would be: nPk = n! / (n-k)!

nPk = 6 / (3 - 3)!

= 6 / 0!

= 6 (it means 6 possible permutations)

Because n = 3!, therefore:

3! = 3 * 2 * 1

= 6 ( n = 6 )

I just need to know the algorithm on how to do 6! in java using for-loops only. Thank you :)

Answer 1

please see,

int n=3, fact = 1;
for (; n > 0; n--) {
    fact = fact * n;
}

System.out.println("The result is " + fact);

Answer 2

Try this:

    public class Try
{
public static void main(String[] args){
    int n=3;
    int fact=1;
    for(int i =n;i>0;i--)
    {
        fact=fact*i;
    }
    System.out.println(fact);
    }

}

n is the number whose factorial is to be found.

Answer 3

Try This,

Scanner keyboard = new Scanner(System.in);
int i = keyboard.nextInt();
fact = 1;
for (int n=i; n > 0; n--)
  fact = fact * n;

System.out.println("The result is " + fact);