Function Factorial

Proposed exercise

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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

Output

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Solution

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

public static void Main()
{
Console.WriteLine("Number:");
int n = Convert.ToInt32(Console.ReadLine());

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