Write a Java program to calculate the factorial of a given number using recursion.

This program demonstrates the calculation of a factorial using recursion. The key element is the factorial method, which calls itself to compute the product of numbers from n down to 1. Here’s a detailed breakdown:

class Main {
    public static void main(String[] args) {
        int number = 5;  // Input number for factorial calculation
        int result = factorial(number);  // Calculate factorial
        // Properly format the output to display the result
        System.out.println("Factorial of " + number + " is " + result);
    }

    // Recursive method to calculate factorial
    public static int factorial(int n) {
        if (n == 0 || n == 1) {
            return 1;  // Base case: factorial of 0 or 1 is 1
        } else {
            return n * factorial(n - 1);  // Recursive case
        }
    }
}

Output:

Factorial of 5 is 120

How It Works
Main Method
number:
Set to 5 as an example input. You can replace it with any positive integer.

factorial(number):
Calls the recursive factorial method to compute the factorial of number.

Print Statement:
Outputs the formatted result as:

Factorial of 5 is 120
Recursive factorial Method

Base Case:
If n == 0 or n == 1, return 1. This prevents infinite recursion and handles the simplest cases.
Recursive Case:
For any n > 1, return n * factorial(n – 1). This breaks the problem into smaller pieces by repeatedly decreasing n until reaching the base case.

Example Execution for number = 5

Advantages of Recursive Approach
Intuitive Design:
Directly reflects the mathematical definition of factorial.

Compact Code:
Avoids explicit loops for clarity.

Considerations
Stack Overflow:
Recursion depth is limited by the system stack size. For very large inputs (e.g., n > 10,000), use an iterative approach instead.

Performance:
Recursion has overhead due to multiple function calls. Iterative methods are generally faster for large n.