Need help understanding how to flag a number in relation to arrays. PLEASE

[Poppa Mintin]

I am having trouble figuring out a way to mark a number as already in use so said number is not repeated. Any suggestions or know of any videos that can be helpful?
Here is my program so far I highlighted where I am having trouble:

Try this:

Add an invisible, unsorted ListBox.

'Add' to the ListBox all the numbers you wish to use. A straight 1 to however many will do. (Doesn't have to start at 1 of course)

While the ListBox count is > 0
Generate a random number between 0 and ListBox.items.Count -1.

Use the number in that ListBox Index as the selected number.
Remove that index from the ListBox.
(the count will now be one less and the remaining higher numbers will have all moved down one)

This way you can only pull out unused numbers, and you don't have to wait for your RNG to find an unused number, which can take quite a while when you're down to the last few remaining numbers especially.

Poppa.


Oh... I see that's more or less what Funky Dexter's suggested.

Pop.

[jmcilhinney]

Try this:

Add an invisible, unsorted ListBox.

No. Never do that. That would be like using an invisible TextBox to store a String. The whole point of controls is to interact with the user. If there's no interaction then there should be no control. That rule might be broken for complex tasks that only a WebBrowser or RichTextBox can do but if all you want to do is store a list of items then just use an array or collection. If you use a ListBox, its Items property is a collection so why have the useless control attached?

On another note, you might also create a randomised list in the first place and then just take the items one by one from the top of the list. You can follow the CodeBank link in my signature below and find a couple of threads on random items from lists.