Simple memoize function in C# along with client calling code.

memoize-client.cs

// Raw Add method
public static int Add(Tuple<int, int> numbers)
{
    return numbers.Item1 + numbers.Item2;
}

static void Main(string[] args)
{
  // Memoized version of Add
  var add = Memoize<Tuple<int, int>, int>(Add);
    
  add(Tuple.Create(5, 10)); // Adding (5,10) to cache
  add(Tuple.Create(5, 10)); // Cache hit for (5,10)
}

memoize.cs

public static Func<TArg,TResult> Memoize<TArg, TResult>(Func<TArg, TResult> code)
{
    var cache = new Dictionary<TArg, TResult>();
    return (TArg input) =>
    {
        TResult result;
        var resultIsCached = cache.TryGetValue(input, out result);
        if (resultIsCached)
        {
            Console.WriteLine("Cache hit for {0}", input.ToString());
            return result;
        }

        result = code(input);
        Console.WriteLine("Adding {0} to cache", input.ToString());
        cache[input] = result;
        return result;
    };
}