Priklad 1 - Bez rekurzie [w/o Recursion]:

 
        public static int Factorial(int x)
        {
            if (x < 0)
            {
                throw new ArgumentException("The argument is negative ");
            }
            
            int result = 1;
            for (int i = 2; i <= x; i++)
            {
                result *= i;
            }
            return result;
        }

Priklad 2 - S rekurziou [ w/ Recursion]:

        public static int Factorial(int x)
        {
            if (x < 0)
            {
                throw new ArgumentException("The argument is negative ");
            }

            if (x==0 || x==1)
            {
                return 1;
            }
            return x * Factorial(x - 1);
        }

Priklad 3 - IEnumerable:

        public static IEnumerable<int> Factorial(int x)
        {
            if (x < 0)
            {
                throw new ArgumentException("The argument is negative ");
            }

            if (x == 0)
            {
                yield return 1;
            }

            int startIndex = 1;

            while (startIndex <= x)
            {
                yield return startIndex;
                startIndex++;
            }
        }

Priklad 4 = LINQ:

       
        public static int Factorial(int x)
        {
            return Enumerable.Range(1, x).Aggregate((i, r) => r * i);
        }