CODEWITHSUNDEEP
c#random
Rafał Developer
Rafał Developer

Reputation: 2055

Random similar draw sequences

A lot of times when I draw numbers I get 0 and all the time I can see similar draw sequences. Do you know why?

For example: losowanie(3) -> result 0 some times 1?

Code:

 public int losowanie(int w)
        {
            Random rand = new Random(Guid.NewGuid().GetHashCode());
            int s = w - 1;
            return rand.Next(0, s);
        }

Code:

enter image description here

Upvotes: 1

Views: 92

Answers (2)

rene
rene

Reputation: 42444

Instantiate your Random class once and reuse that instance. For example by having a private static field in the class that utilizes the Random sequence. As an aside: I doubt a default seed with Guid.NewGuid() will give better results as to the the parameterless contructor of Random(). 

public class whatever
{
        static Random rand = new Random(Guid.NewGuid().GetHashCode());
        // or use new Random(); 

        public int losowanie(int w)
        {
            int s = w - 1;
            return rand.Next(0, s);
        }
}

Upvotes: 1

Marek Grzenkowicz
Marek Grzenkowicz

Reputation: 17353

The behavior you're seeing is correct - losowanie(3) calls rand.Next(0, 2) so only two values can be returned - either 0 or 1.

You may misunderstand the meaning of Random.Next(minValue, maxValue) parameters - check MSDN for details.

Upvotes: 1

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