Microsoft Dynamics AX (Archived)

Random Number Generation

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Posted on by Community Member

Hello,

We are implementing one functionality where we need to generate random number between 5 digits to 9 digits.

First I tried with

//Job 1

Random Random = new Random();
int myrandomnumber;
;
myrandomnumber= Random.nextInt() ;

In above job it is generating random number of 5 digits and it seems everytime number starts with 30***. We tried to generate two random numbers and linked them.

Suppose we need to generate 7 digits number then 5 digit by above job and 2 digits by myrandomnumber= Random.nextInt() mod 100 ; and then linked them but it generates 1 digit number also. So we can not rely on this functions.

Then I tried to generate random number using

//Job 2

RandomGenerate randomGenerate;
randomGenerate = RandomGenerate::construct();
randomGenerate.parmSeed(new Random().nextInt());

switch(numberOfDigits)
{

case 5:
RandomNo = randomGenerate.randomInt(10001,99999);
break;

case 9:
RandomNo = randomGenerate.randomInt(100000001,999999999);
break;
}

This is good option but in this while we are generating numbers of 9 digits mostly they are starting from 999/998/997. I never get number starting from 1 to 8. Can anyone explain why this is happening? Is there any alternate approach we can use to generate random numbers those are actually random?(any number from entire range)

Thanks in advance!

Regards,

Smit

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Mea_ 60,284 on at

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Hi Smit Patel,

If I were you, I would use System.Random, did you try it ?

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Martin Dráb 237,976 Most Valuable Professional on at

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The logic responsible for the behavior is in RandomGenerate.randomInt(). I agree that it seems to work incorrectly, so simply don't use it (and you can report it as a bug to Microsoft).

You have several workarounds.

Take X++ class Random and covert nextInt() to the required range by yourself. That's exactly what randomInt() tries to do.

System.Random, mentioned by Ievgen, already supports the range (Next(int, int)), so this is likely the easiest option.

If you need something better (such as not using the same seed for all instances created in the same millisecond, for example), consider Inferno's CryptoRandom.

By the way, what's the point of randomGenerate.parmSeed(new Random().nextInt());? Your seed is based on a new instance of Random, where you use the default seed anyway, so it's not going to improve anything.

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Community Member on at

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Hi Martin/Ievgen,

Thanks for your reply.

I had not tried system.random in past anytime. It is new for me. But after using same it seems it is very easy to use it. It worked for my case.

Martin, I understood first and second approach but second seems more easy. Yes and that line of randomGenerate.parmSeed(new Random().nextInt()); is not of any use I checked.

Regards,

Smit Patel

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