Question

If there is a for loop like

for ( int i = 0; i <= 10; i++ )
{
   //block of code
}

What I want to achieve is, after first iteration i value need not to be 1, it can be anything from 1 to 10, i should not be 0 again and similarly for other iterations.

Answer 1

Simple algorithm:

• create an array containing numbers from 0 to 10
• shuffle
• iterate over that array and retrieve the corresponding index in the initial collection

In Java:

public static void main(String[] args) throws Exception {
    List<Integer> random = Arrays.asList(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
    Collections.shuffle(random);

    List<String> someList = Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k");

    for (int i : random) {
        System.out.print(someList.get(i));
    }
}

outputs:

ihfejkcadbg

EDIT

Now that I reread it, you could also simply shuffle the initial collection and loop:

public static void main(String[] args) throws Exception {
    List<String> someList = Arrays.asList("a", "b", "c", "d", "e", "f", "g", "h", "i", "j");

    //make a copy if you want the initial collection intact
    List<String> random = new ArrayList<> (someList);
    Collections.shuffle(random);

    for (String s : random) {
        System.out.print(s);
    }
}