For Loops Not Always Updating C#

Question

I've run into a strange issue. When I run the following code, each of my text boxes get's filled with the same randomly generated number.

public void diceAdd()
    {
        int[] die = new int[4];
        for(int i = 0; i < total.Length; i++)
        {
            for (int r = 0; r < die.Length; r++)
            {
                //Simulates rolling a 6 sided die
                Random rand = new Random();
                randomNumber = rand.Next(1, 7);
                die[r] = randomNumber;
            }
            int smallest = die[0];
            for (int c = 1; c < die.Length; ++c)
            {
                if (die[c] < smallest)
                {
                    smallest = die[c];
                }
            }
            total[i] = die[0] + die[1] + die[2] + die[3] - smallest;
        }
        strTxt.Text = total[0].ToString();
        dexTxt.Text = total[1].ToString();
        conTxt.Text = total[2].ToString();
        intTxt.Text = total[3].ToString();
        wisTxt.Text = total[4].ToString();
        chaTxt.Text = total[5].ToString();

The thing is, if I add this messagebox

MessageBox.Show(i.ToString());

after

total[i] = die[0] + die[1] + die[2] + die[3] - smallest;

the numbers each get unique outputs, as intended.

I'm thinking it has something to do with threading, but figured I'd ask here before messing something up.

total is just an int array created outside of this portion of code. — Dylan, Jun 17 '15 at 13:51

score 4 · Accepted Answer · edited May 23 '17 at 12:29

4

you are recreating the random number generator every time in the loop, create one before the loop:

  Random rand = new Random();

  for(int i = 0; i < total.Length; i++)
  {
    ...
  }

see also here and here, it explains why the numbers don't change

edited May 23 '17 at 12:29

Community

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1

answered Jun 17 '15 at 13:48

thumbmunkeys

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Oops. Simple answer, thanks for the help! – Dylan Jun 17 '15 at 13:50
@Dylan I would take a look at [this one](http://stackoverflow.com/a/768001/2307070) also – Thomas Ayoub Jun 17 '15 at 13:53
@Thomas that's a good answer, I added it – thumbmunkeys Jun 17 '15 at 13:55

For Loops Not Always Updating C#

1 Answers1