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(IN JAVA) The formula for computing the number of ways of choosing r different t

ID: 3776714 • Letter: #

Question

(IN JAVA)

The formula for computing the number of ways of choosing r different things from a set of n things is the following:

C(n,r) = n! / r!(n-r)!

In this formula, the factorial function is represented by an exclamation point (!) and defined as the product.

                                                n! = n * (n – 1) * (n – 2) * … * 1

Discover a recursive version of the C(n, r) formula, and write a recursive method that computes the value of the formula. Embed the method in a program and test it.

Explanation / Answer

class Factorial
{
   static int factorial(int n)
   {
       if (n == 0)
       {   
           return 1;
       }
else
       {
           return(n * factorial(n-1));
       }
   }
    public static void main(String args[])
   {
       int i,n,fact=1;
Scanner s = new Scanner(System.in);
       System.out.println("Enter a number:");
n=s.nextInt();
       fact = factorial(n);   
       System.out.println("Factorial of "+n+" is: "+fact);
    }
}