using System;

​

​

​

public class Program

{

    public static void Main()

    {

          Console.WriteLine(Tests.AreEqual(Power.CopmutePower(3, 0), 1));

          Console.WriteLine(Tests.AreEqual(Power.CopmutePower(2, 3), 8));

          Console.WriteLine(Tests.AreEqual(Power.CopmutePower(5, 2), 25));

          Console.WriteLine(Tests.AreEqual(Power.CopmutePower(5, -2), 0.04));

​

    }

    static class Tests

    {

        public static string AreEqual(double expected, double actual)

        {

            return expected == actual ? string.Format("Test Passed- Expected {0} - Actual {1}" , expected , actual) 

                : string.Format("Test Failed - Expected {0} - Actual {1}", expected , actual);  

        }

    }

    static class Power

    {

​

        public static double CopmutePower(double x , double n)

        {

            // base case

            if (n == 0)

            {

                return 1;

            }

​

            //  n is negative 

            else if (n < 0)

            {

                return 1 / CopmutePower(x, -n);

            }

            // n is odd

            else if (IsOdd(n))

            {

                return x * CopmutePower(x, n - 1);

            }

            // n is even

            else if (IsEven(n))

            {

                var y = CopmutePower(x, n / 2);

                return y * y;

            }

            else

            {

                return 0;

            }

​

        }

        static bool IsEven(double n)

        {

            return n % 2 == 0;

        }

​

        static bool IsOdd(double n)

        {

            return !IsEven(n);

        }

    }

}

​