Interview Question for Software Development Engineer In Test (SDET) at Microsoft:

//Imports
using System;

//Test class
class Test
{
    //Constructor
    public Test()
    {
        //Nothing
    }

    public int RecursiveExp(int x, int n)
    {
        //First base case
        if (n == 0)
        {
            return 1;
        }

        //Second base case
        if (n == 1)
        {
            return x;
        }

        //Even values of (n)
        if (n % 2 == 0)
        {
            int y = RecursiveExp(x, n / 2);
            return y * y;
        }
        //Odd values of (n)
        else
        {
            int y = RecursiveExp(x, n - 1);
            return x * y;
        }
    }
}

//Main class
class Program
{
    //Main
    static void Main(string[] args)
    {
        //Create a test object
        Test tst = new Test();

        //Examples
        Console.Out.WriteLine(tst.RecursiveExp(2, 0));
        Console.Out.WriteLine(tst.RecursiveExp(2, 1));
        Console.Out.WriteLine(tst.RecursiveExp(2, 3));
        Console.Out.WriteLine(tst.RecursiveExp(2, 4));
    }
}