Function Factorial - Tutorial C# Sharp

Lesson 5:

Functions

Exercise 5.18:

Function Factorial

Objetive:

The factorial of a number is expressed as follows:

n! = n · (n-1) · (n-2) · (n-3) · ... · 3 · 2 · 1

For example,
6! = 6·5·4·3·2·1

Create a recursive function to calculate the factorial of the number specified as parameter:

Console.Write ( Factorial (6) );

would display 720

using System;
public class Exercise120
{
    public static int Factorial(int num)
    {
        if (num == 0)
            return 1;
        else
            return num * Factorial(num - 1);
    }

    public static void Main()
    {
        Console.WriteLine("Enter a number:");
        int number = Convert.ToInt32(Console.ReadLine());

        Console.WriteLine(Factorial(number));

        Console.WriteLine(Factorial(6));
    }
}