using System;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var freq = new int[20];
            var rng = new RandomNumberGenerator();
            for (int i = 0; i < 100; i++)
            {
                var rnd = rng.Next(20);
                freq[rnd] += 1;
                Console.Write("{0}, ", rnd);
            }

            Console.WriteLine("Done.");
            for (int i = 0; i < 20; i++)
            {
                Console.Write("{0}={1}\t", i, freq[i]);
            }
            Console.ReadLine();
        }
    }

    // Based on https://en.wikipedia.org/wiki/Linear_congruential_generator
    class RandomNumberGenerator
    {
        private const long m = 4294967296; // aka 2^32
        private const long a = 1664525;
        private const long c = 1013904223;
        private long _last;

        public RandomNumberGenerator()
        {
            _last = DateTime.Now.Ticks % m;
        }

        public RandomNumberGenerator(long seed)
        {
            _last = seed;
        }

        public long Next()
        {
            _last = ((a * _last) + c) % m;

            return _last;
        }

        public long Next(long maxValue)
        {
            return Next() % maxValue;
        }
    }
}