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


Solution

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) );
    }
}

Popular Posts