public/subjects/java/checkpoints/factorial

Factorial

Instructions

In a file named Factorial.java write a function factorial that calculates the factorial of a non-negative integer given as a parameter.

The factorial of a non-negative integer n (denoted as n!) is the product of all positive integers less than or equal to n. For example, 5! = 5 × 4 × 3 × 2 × 1 = 120.

Note: The factorial of 0 is 1, according to the convention

Expected Functions

public class Factorial {
    public static Integer factorial(Integer n) {
        // your code here
    }
}

Usage

Here is a possible ExerciseRunner.java to test your function :

public class ExerciseRunner {
    public static void main(String[] args) {
        System.out.println(Factorial.factorial(3));
    }
}

and its output :

$ javac *.java -d build
$ java -cp build ExerciseRunner
6
$