gistfile1.cs

///by Peter Stegnar
///SnippetID: 56dd1bc8-f917-440d-876b-ce4fa816f788 
///Fell free to use - with this header

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

public class MyClass
{
    private delegate int RandomFunction();

    public static void RunSnippet()
    {
        Console.WriteLine("Rand(7) implementation with Rand(5)");
        //Console.WriteLine("Testing Rand(5): " + RandTest(1, 5, Rand5));
        //Console.WriteLine("Testing Rand(7) Native: " + RandTest(1, 7, Rand7Native));
        Console.WriteLine("Testing Rand(7): " + RandTest(1, 7, Rand7WithRand5));
    }

    private static int Rand7WithRand5()
    {
        //PUT YOU FAVOURITE ALGHORITHM HERE//
        
        //1. Stackoverflow winner
        int i;
        do
        {
            i = 5 * (Rand5() - 1) + Rand5();  // i is now uniformly random between 1 and 25
        } while (i > 21);
        // i is now uniformly random between 1 and 21
        return i % 7 + 1; 

        //My 2 cents
        //return (Rand5() + Rand5()) % 7 + 1;
    }

    private static int Rand5()
    {
        Random random = new Random();

        return random.Next(1, 6);
    }

    private static int Rand7Native()
    {
        Random random = new Random();

        return random.Next(1, 8);
    }

    private static bool RandTest(int minRange, int maxRange, RandomFunction randomFunction)
	{
		List<int> listOfMandatoryRands = new List<int>();
        int i = 0;

        do
        {
            int randNum = randomFunction();
            if (randNum < minRange || randNum > maxRange)
            {
                Console.WriteLine("--FALSE RAND: " + randNum);
                return false;
            }
            //Console.WriteLine("--RandNum: " + randNum);
            listOfMandatoryRands.Add(randNum);
            i++;
        } while (TestMandatoryFields(listOfMandatoryRands, minRange, maxRange));
        Console.WriteLine("--ITERATIONS: " + i);

        return true;
	}

    private static bool TestMandatoryFields(IEnumerable<int> listOfMandatoryRands, int minRange, int maxRange)
    {
        //listOfMandatoryRands = listOfMandatoryRands.Where(number => number >= minRange && number <= maxRange).Distinct() as List<int>;
        Console.WriteLine("--DISTRIBUTION: " + DistributionPrinter(listOfMandatoryRands, minRange, maxRange));
        listOfMandatoryRands = (from number in listOfMandatoryRands where number >= minRange && number <= maxRange select number).Distinct();
        Console.WriteLine("--LIST: " + ArrayPrinter(listOfMandatoryRands));

        return listOfMandatoryRands.Count() != maxRange - minRange + 1;
    }

    private static string ArrayPrinter(IEnumerable<int> list)
    {
        string arrayString = String.Empty;

        foreach (int s in list)
        {
            arrayString += s + " ";
        }
        return arrayString;
    }

    private static string DistributionPrinter(IEnumerable<int> list, int minRange, int maxRange)
    {
        string distributionArray = String.Empty;

        for (int i = minRange; i <= maxRange;i++)
        {
            distributionArray += "[" + i + "]" + list.Count(number => number == i).ToString() + " ";
        }
        return distributionArray;
    }

    #region Helper methods

    public static void Main()
    {
        try
        {
            RunSnippet();
        }
        catch (Exception e)
        {
            string error = string.Format("---\nThe following error occurred while executing the snippet:\n{0}\n---", e.ToString());
            Console.WriteLine(error);
        }
        finally
        {
            Console.Write("Press any key to continue...");
            Console.ReadKey();
        }
    }

    private static void WL(object text, params object[] args)
    {
        Console.WriteLine(text.ToString(), args);
    }

    private static void RL()
    {
        Console.ReadLine();
    }

    private static void Break()
    {
        System.Diagnostics.Debugger.Break();
    }

    #endregion
}