Wednesday 1 January 2014

RandomNumberGenerator in C#

To generate random numbers in C#, it is possible to use the class RandomNumberGenerator in System.Security.Cryptography namespace in .NET. This class can be easier to use with a simple wrapper class. The wrapper class provided here returns either an integer or an unsigned integer. The "randomness" is better in this class than in the default Random generator of .NET, the Random class. This class will for example emit the same random values for two instances instantiated at almost the same time of the Random class. The wrapper class looks like this:

 public static class RandomGenerator
    {

        private static readonly RandomNumberGenerator generator;

        static RandomGenerator()
        {
            generator = RandomNumberGenerator.Create();
        }

        public static int GetNext()
        {
            byte[] rndArray = new byte[4];
            generator.GetBytes(rndArray);
            return BitConverter.ToInt32(rndArray, 0);
        }

        public static uint GetNextUnsigned()
        {
            byte[] rndArray = new byte[4];
            generator.GetBytes(rndArray);
            return BitConverter.ToUInt32(rndArray, 0);
        }



    }

The class is in fact a static class with a static RandomNumberGenerator instance created in the static constructor. The methods to create a new random number uses the GetBytes method to fill a four byte array. We could of course generate longer arrays and create for example 64-bits integers, but here just a four byte array is used. Either an integer or unsigned integer is returned by the two respective methods for this. I have not bothered to refactor this simple class. The BitConverter class converts the byte array to int or unsigned int (32-bits) starting at index 0. We could also return other datatypes here than just integers. Simple unit test:

 [TestFixture]
    public class UnitTest1
    {

        [Test]
        public void GetNextInteger()
        {
            int random = RandomGenerator.GetNext();
            Debug.WriteLine(random);
        }

        [Test]
        public void GetNextUInteger()
        {
            uint random = RandomGenerator.GetNextUnsigned();
            Debug.WriteLine(random);
        }

    }

Sample output:

------ Test started: Assembly: TestRandomNumberGeneratorTest.dll ------

-1821995826

1013025195

2 passed, 0 failed, 0 skipped, took 0,42 seconds (NUnit 2.6.2).


If you would like random numbers in a specified range, for example 0 to 99, you could take the integer and do a modulo 100 operation, e.g RandomGenerator.GetNextUnsigned() % 100. Of course, this is tied to the desired range you want. If a range between for example -20 and 20 is desired, you could for example do something like: -20 + (RandomGenerator.GetNextUnsigned() % 41). The bottom line is that you should not entrust the randomness of System.Random class but use the RandomNumberGenerator class in System.Security.Cryptography if you want to generate random integers, signed or unsigned that exhibit more distributed randomness than the pseudorandomness of System.Random.
Share this article on LinkedIn.

15 comments:

  1. Are you looking to make cash from your traffic by using popunder advertisments?
    In case you are, did you take a look at PropellerAds?

    ReplyDelete
  2. greate article what a problem with guid ?

    ReplyDelete
  3. Well Said, you have furnished the right information that will be useful to anyone at all time. Thanks for sharing your Ideas.
    python course in pune
    python course in chennai
    python Training in Bangalore

    ReplyDelete
  4. It seems you are so busy in last month. The detail you shared about your work and it is really impressive that's why i am waiting for your post because i get the new ideas over here and you really write so well.
    Data Science Training in Chennai
    Data Science training in kalyan nagar
    Data science training in Bangalore
    Data Science training in marathahalli
    Data Science interview questions and answers
    Data science training in jaya nagar

    ReplyDelete
  5. I found your blog while searching for the updates, I am happy to be here. Very useful content and also easily understandable providing.. Believe me I did wrote an post about tutorials for beginners with reference of your blog. 
    Data Science Training in Indira nagar
    Data Science Training in btm layout
    Python Training in Kalyan nagar
    Data Science training in Indira nagar
    Data Science Training in Marathahalli

    ReplyDelete
  6. Very nice post here and thanks for it .I always like and such a super contents of these post.Excellent and very cool idea and great content of different kinds of the valuable information's.
    rpa training in bangalore
    best rpa training in bangalore
    rpa training in pune | rpa course in bangalore
    rpa training in chennai

    ReplyDelete
  7. Attend The Python Training in Bangalore From ExcelR. Practical Python Training in Bangalore Sessions With Assured Placement Support From Experienced Faculty. ExcelR Offers The Python Training in Bangalore.

    ReplyDelete
  8. I am looking for and I love to post a comment that "The content of your post is awesome" Great work!
    data analytics course

    ReplyDelete
  9. Your article has all the necessary informative. It is a change of taste from other supposed informational content with some accurate points which needs to be focussed to get the details about the topic.
    SAP training in Mumbai
    SAP course in Mumbai

    ReplyDelete
  10. Writing with style and getting good compliments on the article is quite hard, to be honest.But you've done it so calmly and with so cool feeling and you've nailed the job. This article is possessed with style and I am giving good compliment. Best!
    aws online training in hyderabad

    ReplyDelete
  11. Enroll in the Best Data Science program in Chennai and become a successful Data Scientist.business analytics course in ranchi

    ReplyDelete
  12. I recommend everyone to read this blog as it has some of the best data science content you will find. The best part is that the writer presented the information in an engaging and engaging way. Each line gives you something new to learn, and that says a lot about the quality of the information presented here.

    Kickstart your career by enrolling in this Data Science Certification Course in Chennai

    ReplyDelete
  13. The examples and case studies shared in this post effectively demonstrate the impact of data analytics in various domains.data analytics course in chennai

    ReplyDelete