Using time to determine a 'random' number

Sometimes an opportunity presents itself where you have two answeres and it doesn't really matter which one you use. A good example could be find b in the y=mx+b formula to determain the equation of line between two points. Or in my example, asking "Which came first, the chicken or the egg?"

Code:

---

'Here I just store two answeres
Dim str() As String = {"The Chicken", "The Egg"}

'Here I get the millisecond
Dim timeNow As Integer = DateTime.Now.Millisecond

'Here I use the Mod operator to check if the millisecond is odd or even
If CBool(timeNow Mod 3) Then
    MessageBox.Show(str(0), "Which came first?")
Else
    MessageBox.Show(str(1), "Which came first?")
End If

---

Update:
It has been nearly 9 years since I originally wrote this and I marvel at how far I have come. This is how I would rewrite the code snippet today:

Code:

---

Public Class RandomOption
    Public Shared Function NextRandom(Of T)(options As IEnumerable(Of T)) As T
        If (options.Count() < 2) Then
            Throw New ArgumentException("The underlying collection must have at least two (2) items.")
        End If

        Dim skip = If(DateTime.Now.Ticks Mod 3 = 0, 0, 1)
        Return options.Skip(skip).First()
    End Function
End Class

---

This is how the class could be used, using the same chicken/egg example:

Code:

---

Console.Write("Which came first: ")

Dim answer = RandomOption.NextRandom(Of String)({"Chicken", "Egg"})
Console.WriteLine(answer)

---

Fiddle: https://dotnetfiddle.net/7wGlsU

I'm a little curious as to why you didn't make use of the Random() class, but, you're using time to determine a choice (which, funnily enough, the Random() class has an overload to take a seed, while, if I recall correctly, the default constructor will use the system time as the seed). While that is technically psuedo-random, it can be abused to to get a desired result. Otherwise, a nice small snippet to the Codebank. I recommend you find a way to wrap this up in a class and allow someone to give it a List(Of T) and, using that method, try to see if it will give you random choices.

A nice little exercise, if you ask me.

Thanks for the reply. Reason I didn't use the Random class is because I try to avoid as much as possible. I know in many cases it's best to use Random, but in the case of determain the equation of line example I gave above I was able to avoid it. I will try to wrap it up in a class, seems challenging what you've proposed... I like it! But again, thanks for the reply.

Quote:

---

Originally Posted by dday9

Thanks for the reply. Reason I didn't use the Random class is because I try to avoid as much as possible. I know in many cases it's best to use Random, but in the case of determain the equation of line example I gave above I was able to avoid it. I will try to wrap it up in a class, seems challenging what you've proposed... I like it! But again, thanks for the reply.

---

Just curious, why do you want to avoid it? Is there a particular reason you dislike it?

Because there is never truely a random number. Everything happens because an event triggered it to happen. Not anything to the .Net random, just a personal knitpick.

Quote:

---

Originally Posted by dday9

Because there is never truely a random number. Everything happens because an event triggered it to happen. Not anything to the .Net random, just a personal knitpick.

---

In all fairness, you can't get true randomness with this either, in any language. You can get really good randomization (Blum Blum Shub, and Mersenne Twister are two good implementations of very good, strong randomization algorithms) if you know what you're doing.

If you really want extremely good (but slow) randomization, you're going to need hardware to do it. Otherwise, the .NET randomization class (which I believe implements a Linear Congruential Generator, described here) is pretty good for most needs.

Also, if you want examples for the Mersenne Twister and Blum Blum Shub, I'll be more than happy to post them in the codebank later today when I get home from work.

Mais yeah, I love to see some examples. I love studying the art of "randomizing"

Quote:

---

Originally Posted by dday9

VB.Net Code:

'Here I use the Mod operator to check if the millisecond is odd or even
        If CBool(timeNow Mod 3) Then ...

---

You need to use Mod 2 to check for odd/even, not Mod 3.

Quote:

---

Originally Posted by dday9

Because there is never truely a random number. Everything happens because an event triggered it to happen. Not anything to the .Net random, just a personal knitpick.

---

That really doesn't make sense. How is your algorithm any more random than using the Random class? You know ahead of time exactly what value will be returned for every time of the day.

Hi dday, adding to your woes:

1. It's better to use DateTime.Ticks because a lot of code can be processed in a millisecond. Your code with messageboxes won't show this because you stop the code, but in other circumstances you could easily end up with all eggs or all chickens!

2. The example of the line formula y = mx + b is not good because it has only one solution for b. There are other line formulas involving angles where there could be two solutions, corresponding to the directions AB or BA. You would usually use those when the direction does matter. If it really doesn't matter, you don't need a randomizer because you can take whichever solution comes first.

BB

Thanks for all of y'alls suggestions and input. I know that this isn't "random", but I did find it unique. I will state again, that I have a huge intrest in randoms and randomizing. This is just an extension of my intrest.

I have updated original post to include how I would do this today.

You have come a long way. Proud of you my child :)

If the Random class is not random enough for you - it absolutely is for the vast majority of applications - then you should be using the RNGCryptoServiceProvider class. It is what's used to generate random numbers for cryptography in .NET. It is random enough for you.