Calculate de double factorial of a number in java!!

 

Double factorial of a number, denoted as n!!, refers to the product of all positive integers from 1 to n, but including only the odd numbers. Calculating the double factorial is a straightforward process in Java. Below, we'll show you how to do it with a concise example of code:

public class DoubleFactorial {

    public static int calculateDoubleFactorial(int n) {

        int result = 1;

        

        // Start from n and decrement by 2 until reaching 1 or 0.

        while (n >= 1) {

            result *= n;

            n -= 2;

        }

        

        return result;

    }

    

    public static void main(String[] args) {

        int number = 5; // Change this value to the desired number.

        int result = calculateDoubleFactorial(number);

        

        System.out.println("The double factorial of " + number + " is " + result);

    }

}

In this code, we've created a function called calculateDoubleFactorial that takes an integer n as input and calculates its double factorial. We use a while loop to multiply all odd numbers from n down to 1 or 0, decrementing n by 2 in each iteration. Finally, the result is returned and displayed in the main method of the program.

If you run this code with number set to 5, you'll get the double factorial of 5, which is 15. You can change the value of number according to your needs to calculate the double factorial of any positive integer. We hope this article has helped you understand how to calculate the double factorial in Java quickly and easily!