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Generating random Number in an interval

 

Generating random Number in an interval
m.babanfati

3 Jul, 2009 - 01:37 AM
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Hello All;

I want to generate a random number (integer) between 15 and 30; and after consulting several tutorials on random number generation, I learnt I can do what I want by simply executing the following code

CODE

cout << rand() % 30 + 15;


Although most of the times, I get a number within the range; but to my surprise, many at times I get a value above the limit (outside the interval), like say 41, 39, 32, 33 and so on.

please how can I do away with this problem.
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venkateshps

RE: Generating Random Number In An Interval

3 Jul, 2009 - 02:45 AM
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The statement you have written will generate numbers between 15 to 45.
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venkateshps

RE: Generating Random Number In An Interval

3 Jul, 2009 - 02:57 AM
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try this

int t=rand() % 30;

if (t<=15)
cout<<t+ 15<<endl;
else
cout<<t<<endl;
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m.babanfati

RE: Generating Random Number In An Interval

3 Jul, 2009 - 03:02 AM
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Thank you for clarifying what my output will always be. I now got the logic and solved the problem

thanks once again
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ComputerAnalysis

RE: Generating Random Number In An Interval

3 Jul, 2009 - 11:51 AM
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Better yet the following code accomplishes the same task and is more efficient because no check is required.

CODE

int t = rand() % 16 + 15


This will generate pseudo-random within the range of 15 to 30 without a check.
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