Question

I can create random numbers from a range using

Random rand = new Random();
int num = rand.nextInt(10);
System.out.println("Generated Random Number between 0 to 10 is : " + num);

But if i need the next random number generated to be a part of the range minus the already generated one, will keeping the above statement in a loop will suffice?

Also I need to stop once i exhaust all the number from the range.

For eg,

The code gives me a random number between [0-10],

1st - 4 – range {[0-10]}

2nd - 9 – range {[0-10]-4}

3rd - 8 – range {[0-10]-4,9}

..

..

10th - 10 – range {[0-10]-[0-9]}

Will this function output from [Range]{this is my requirement} or (Range)? Or is there any better alternative solution?

Answer 1

The easiest way would probably be to:

• put the numbers (0 to 10) in a list
• call Collections.shuffle() on that list
• loop over the list

Something like:

List<Integer> numbers = Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 8, 10);
Collections.shuffle(numbers);
System.out.println(numbers);

You can even provide a random generator for the shuffling operation if the default doesn’t suit you.