The FizzBuzz problem

By pcurd

Amy Kimber posted an article today referring to a post from Nick Telford on twitter:

Will The Real Programmers Please Stand Up? http://retwt.me/1NEBw // another example of how diluted our industry really is (link)

This interests me as I often find job interviews to be very generic and after about four in a row you get to know all the answers and appear much cleverer than you perhaps are.  I like a problem that makes you think and although FizzBuzz is a trivial problem, I wanted to answer it with a little bit of real world thinking.

To quote Amy, the FizzBuzz problem is “The idea is simple, all you have to do is write a program that prints out the numbers 1 to 100, but for multiples of 3, print Fizz instead of the number and for multiples of 5 print Buzz. If the number is a multiple of both, FizzBuzz should be printed.”

In the real world, specs change. Today it’s 3 and 5 and tomorrow it’s 4 and 9 and we need to add an extra one “Bibble” for 11.  I decided to solve the problem with a list of number and word pairs so that changing it would be easy.  .Net provides a nice KeyValuePair generic which I used as Int,String.

Originally I had this implemented using a Dictionary but as FizzBuzz must be implemented the correct way around (not BuzzFizz) I needed to change this to a SortedDictionary to ensure order of execution.

Code is as below:

using System;
using System.Collections.Generic;

namespace FizzBuzz
{
    class Program
    {
        static ICollection<KeyValuePair<int, string>> wordlist;
        static void Main(string[] args)
        {
            wordlist = new SortedDictionary<int, string>();
            wordlist.Add(new KeyValuePair<int, string>(3, "Fizz"));
            wordlist.Add(new KeyValuePair<int, string>(5, "Buzz"));
            PrintFizzBuzz(1, 100);
            Console.ReadKey();
        }

        static void PrintFizzBuzz(int start, int finish)
        {
            for (int i = start; i <= finish; i++)
            {
                Console.WriteLine(CalculateFizzBuzz(i));
            }
        }

        static object CalculateFizzBuzz(int i)
        {
            string CalculateFizzBuzz = "";
            foreach (KeyValuePair<int, string> word in wordlist)
            {
                if (i % word.Key == 0)
                    CalculateFizzBuzz += word.Value;
            }
            if (CalculateFizzBuzz.Length == 0)
                CalculateFizzBuzz = i.ToString();

            return CalculateFizzBuzz;
        }
    }
}