Online examination system

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ASP.NET

when i am selecting question randomly from database,same question is repeated more than once.how can I solve this?

Posted 26-May-10 21:08pm

NileshPandey

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Abhinav S 27-May-10 3:11am

Reason for my vote of 1
What have you tried so far? What you have asked is homework to me.

R. Giskard Reventlov 27-May-10 3:28am

Sounds like it's not quite as random as you think it is. How do you evaluate that the selection is, indeed, random?

BTW: do you understand that writing a question in txtspk is rude and makes you look like a child trying to get their homework done. A big no-no round here.

2 solutions

Solution 2

Receiving the following output from a random number generator is perfectly valid, if not very likely:

1, 1, 1, 1, 2, 1, 1, 1

It is, after all, a set of random numbers. However, to get around your problem, why not maintain a list of questions not asked, and then pick a random index from that list. Then it's impossible to get a repeated question, even if the random number is the same every time (provided you remember to remove the question from the list once asked).

Posted 26-May-10 23:08pm

Tony Richards

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OriginalGriff · Accepted Answer · 2010-05-26T21:40:00

This is a bit of a guess, without seeing your code it is difficult to tell what you are doing wrong. However, the most common error when using random numbers is to re-create the randomiser repeatedly:

for (int i = 0; i < 10; i++)
   {
   Random r = new Random();
   outputMyRandomNumbers[i] = r.Next();
   }

This will generate the same number several times in a row, possibly every time depending on when it happens, processor speed, etc.

Change it to a single instance:

Random r = new Random();
for (int i = 0; i < 10; i++)
   {
   outputMyRandomNumbers[i] = r.Next();
   }

And all will be well.