Why my created random function just work for one time?

Question

Thank you for helping me!

There is a piece of random function I found on the Internet, called GetRandom. I put it like below

 public static double GetRandom(double[] array)
　　{    
　      Random ran = new Random();
　　　　int n = ran.Next(array.Length);
　　　　return array[n];
　　}

 private void Window_Activated(object sender, System.EventArgs e)
    {   


        c1 = c-GetRandom(arr);
        c2 = c-GetRandom(arr);
......

    }

arr is a double arry containing a a few doubles. c1,c2,c3 .... are all double. Howeve, it seems that every GetRandom(arr) in the last few lines return the same result.How come? The n in GetRandom can't be refreshed after each use?

You don't need many Randoms. One `Random` can generate infinite random numbers. — Theodor Zoulias, Apr 24 '19 at 19:10
The official documentation describes this behavior. Consult it often. — Ňɏssa Pøngjǣrdenlarp, Apr 24 '19 at 19:28

Hien Nguyen · Accepted Answer · 2019-04-24T20:04:02.940

0

You need move create Random outside function by create Random ran = new Random(); in class scope.

 Random ran = new Random();
 public static double GetRandom(double[] array, Random ran)
    　　{     
    　　　　int n = ran.Next(array.Length);
    　　　　return array[n];
    　　}

private void Window_Activated(object sender, System.EventArgs e)
    {   

        c1 = c-GetRandom(arr, ran);
        c2 = c-GetRandom(arr, ran);

    }

edited Apr 24 '19 at 20:04

answered Apr 24 '19 at 19:02

Hien Nguyen

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I updated answer move out random as class scope, remove vote down please – Hien Nguyen Apr 24 '19 at 20:04

Why my created random function just work for one time?

1 Answers1