# 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

## Source Code:

```
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));
}
}
```

Exercisey
5.18