C# script to calculate factorial of a number

factorial.csx

// $ dotnet script factorial.csx 10
// 3628800

var n = long.Parse(Args.ElementAt(0));

Console.WriteLine($"{factorial(n)}");

long factorial(long n)
{
    if (n == 0) {
        return 1;
    }
    return n * factorial(n - 1);
}