a buddy of mine, Scott, asked if tap could be done in PHP and Perl. Probably, but i wanted to write it in c#. reference - http://moonbase.rydia.net/mental/blog/programming/eavesdropping-on-expressions

TapExample.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int k = 3;
            int q = 5;
            int t = 3;
            float ans = 0;
            ans = (k + 1) / (tap((q - t)) / 2);
            Console.WriteLine(ans.ToString());
            Console.ReadKey();
        }

        static dynamic tap (dynamic arg)
        {
            object returnValue = arg;
            Console.WriteLine("tap: " + returnValue.ToString());
            return returnValue;
        }
    }
}

result:
tap: 2
4

p.s.
dynamic is a .NET 4.0 thing. it's not available in previous versions.