remove duplicates inside random generated arrays

Asked Jul 19 '16 at 13:21

Active Jul 19 '16 at 13:21

Viewed 35 times

I am a bit new to Java so I hope I can get some help here. I created a random number generator that gets told how many numbers it's supposed to generate. Problem is that my version allows for duplicates which I do not want.

public int[] rng()
{           
    Scanner scan1 = new Scanner(System.in);
    System.out.println("How many numbers do you want generated?");
    int rng_length = scan1.nextInt();
    System.out.println("Number range");
    int rng_range = scan1.nextInt();            
    scan1.close();
    int anArray [] = new int[rng_length]; 
    for (int i = 0; i < anArray.length; i++)
    {
        anArray[i] = (int) (Math.random()* rng_range) + 1;
    } 
  Arrays.sort(anArray);
  System.out.println(Arrays.toString(anArray));
  return anArray;  
}

What do I need to change in order to avoid duplicates? Preferably I'd want the array to be created, then analyzed for duplicates and those duplicates get re-rolled till they aren't any duplicates any longer but I have no clue how to do that.

asked Jul 19 '16 at 13:21

Gremmy

"re-rolling till there aren't any duplicates" can take a long time. Easier to add the numbers in sequence and shuffle. – Andy Turner Jul 19 '16 at 13:25
You can use instead of `Math.random()`, `Collection.shuffle` – wake-0 Jul 19 '16 at 13:26
Can you make an example for that? – Gremmy Jul 19 '16 at 14:05

remove duplicates inside random generated arrays

0 Answers0