Dice program not calculating correctly?

Question

I am trying to make a dice program. So when you click roll, it is supposed to roll two dice and add the sums and that's the number you roll. I need some help with this windows form program. Here is some code:

private int totalRolls;

private void btnRoll_Click(object sender, EventArgs e)
{
    totalRolls += 1;

    System.Random Int1 = new System.Random((int)System.DateTime.Now.Ticks);
    System.Random Int2 = new System.Random((int)System.DateTime.Now.Ticks);

    int randomInteger1 = Int1.Next(1, 7);
    int randomInteger2 = Int2.Next(1, 7);

    lblNumberRolled.Text = randomInteger1.ToString() + randomInteger2.ToString();

The code for lblNumberRolled.Text I don't think is right. That is the code to add both dice up to get final sum number of dice. But when I run it, it shows big numbers like 30 and stuff. It isn't adding or something.

The highest sum should be 12.

possible duplicate of [Random number generator only generating one random number](http://stackoverflow.com/questions/767999/random-number-generator-only-generating-one-random-number) — Alexei Levenkov, Oct 24 '13 at 05:37
Side note 2: Please try to provide minimal sample code that shows problem. Check out http://www.sscce.org for guidance. — Alexei Levenkov, Oct 24 '13 at 05:41
use lblNumberRolled.Text = (randomInteger1 + randomInteger2).ToString(); — DevEstacion, Oct 24 '13 at 05:52

Dannydust · Accepted Answer · 2013-10-24T05:59:06.970

4

Change your code to:

lblNumberRolled.Text = (randomInteger1 + randomInteger2).ToString();

Explanation:

randomInteger1.ToString() +  randomInteger2.ToString()

When randomInteger1 is 2 then you make a string of it it will be "2" + when randominterger2 is 1 after to String it is "1". When you concat these Strings with + you do "2" + "1" and that's 21 and not 3.

And there is another problem with your code: The Ticks object is of Type long and you cast it to int. So you loose information. This leads to that you will get most of the time the same seed for your both ints. And that leads to that you will get most of the timethe same random integers.

Putting a Thread.Sleep(20) between your random calls will fix it:

System.Random Int1 = new System.Random((int)System.DateTime.Now.Ticks);
Thread.Sleep(20);
System.Random Int2 = new System.Random((int)System.DateTime.Now.Ticks);

edited Oct 24 '13 at 05:59

answered Oct 24 '13 at 05:38

Dannydust

763
5
8

Thanks it worked. :) Who knew that putting the parenthesis around the wrong thing could totally screw up the code haha. Thanks everyone! – Gunnar Oct 24 '13 at 05:44
1

Please address the "randomness" part too for complete answer. – Alexei Levenkov Oct 24 '13 at 05:44
Updated my answer. I hope this is what you meant? – Dannydust Oct 24 '13 at 05:59
2

Instead of Thread.Sleep(20); you should reuse System.Random instance by calling Int1.Next(1,7); – borkovski Oct 24 '13 at 06:04
+1 Haha that's true! It's so much easier and faster than my Thread.Sleep – Dannydust Oct 24 '13 at 06:11
+1. Yes... Also I expected you to pick guidance from http://stackoverflow.com/questions/767999/random-number-generator-only-generating-one-random-number... – Alexei Levenkov Oct 24 '13 at 06:36

score 2 · Answer 2 · answered Oct 24 '13 at 05:41

This is because you are using a + for string. When you use '+' with strings the compiler thinks of it not as a math operation rather than a concatenation operator.

Try the following

Instead of

lblNumberRolled.Text = randomInteger1.ToString() + randomInteger2.ToString();

Try

lblNumberRolled.Text = Convert.ToString(randomInteger1+randomInteger2);

score 0 · Answer 3 · answered Oct 24 '13 at 08:35

You can do it like this:

Label lb = new Label();
Random random = new Random();
int ranNum1 = random.Next(1, 7); // random num 1-6
int ranNum2 = random.Next(1, 7); // random num 1-6
lb.Text = Convert.ToString(ranNum1 + ranNum2);
Form.Controls.Add(lb);

which means you want something like:

Random random = new Random();
randomInteger1 = random.Next(1,7);
randomInteger2 = random.Next(1,7);
lblNumberRolled.Text = Convert.ToString(randomInteger1 +randomInteger2);

Dice program not calculating correctly?

3 Answers3