C# program to find factorial of a number using recursion

Here's a C# program that finds the factorial of a number using recursion:

using System;

class Program
{
    static void Main()
    {
        int number = 5;

        long factorial = CalculateFactorial(number);

        Console.WriteLine("Factorial of " + number + " is: " + factorial);
    }

    static long CalculateFactorial(int number)
    {
        // Base case: factorial of 0 or 1 is 1
        if (number == 0 || number == 1)
        {
            return 1;
        }
        else
        {
            // Recursive case: factorial of number is number multiplied by factorial of (number - 1)
            return number * CalculateFactorial(number - 1);
        }
    }
}

In this program, we have the CalculateFactorial method that takes an integer number as input and returns the factorial of that number.

We have a base case where if the number is 0 or 1, we return 1, as the factorial of 0 or 1 is 1.

In the recursive case, we calculate the factorial of number by multiplying number with the factorial of (number - 1). We make a recursive call to CalculateFactorial with the value (number - 1).

The recursive calls continue until we reach the base case (number equals 0 or 1), at which point the recursion stops and the factorial value is calculated.

Factorial of 5 is: 120

The factorial of 5 is calculated as 5 * 4 * 3 * 2 * 1, which equals 120.