Fibonacci with Memoization

Program.cs

class Program
{
    static Dictionary<int, int> nums;

    static void Main(string[] args)
    {
        int testNum = 35;
        int loops = 20;

        nums = new Dictionary<int, int>();
        nums.Add(0, 0);
        nums.Add(1, 1);

        Stopwatch sw = Stopwatch.StartNew();
        for (int i = 0; i < loops; i++)
        {
            fib(testNum);
        }
        sw.Stop();
        Console.WriteLine("Time used (fib): {0} ms", sw.Elapsed.TotalMilliseconds);
        sw.Reset();

        sw.Start();
        for (int i = 0; i < loops; i++)
        {
            fibMemo(testNum);
        }
        sw.Stop();
        Console.WriteLine("Time used (fibMemo): {0} ms", sw.Elapsed.TotalMilliseconds);
            
        Console.ReadKey();
    }

    public static int fibMemo(int n)
    {
        if (nums.ContainsKey(n))
        {
            return nums[n];
        }

        int result = fib(n - 1) + fib(n - 2);
        nums.Add(n, result);

        return result;
    }

    public static int fib(int n)
    {
        if (n == 0 || n == 1) {
            return n;
        }
        return fib(n - 1) + fib(n - 2);
    }
}