Java: Add elements to arraylist with FOR loop where element name has increasing number

Question

I have an arraylist where I want to add elements via a for loop.

Answer answer1;
Answer answer2;
Answer answer3;

ArrayList answers = new Array         


        

Answer 1

why you need a for-loop for this? the solution is very obvious:

answers.add(answer1);
answers.add(answer2);
answers.add(answer3);

that's it. no for-loop needed.

Answer 2

Put the answers into an array and iterate over it:

List<Answer> answers = new ArrayList<Answer>(3);

for (Answer answer : new Answer[] {answer1, answer2, answer3}) {
    list.add(answer);
}

EDIT

See João's answer for a much better solution. I'm still leaving my answer here as another option.

Answer 3

That can't be done with a for-loop, unless you use the Reflection API. However, you can use Arrays.asList instead to accomplish the same:

List<Answer> answers = Arrays.asList(answer1, answer2, answer3);

Answer 4

There's always some reflection hacks that you can adapt. Here is some example, but using a collection would be the solution to your problem (the integers you stick on your variables name is a good hint telling us you should use a collection!).

public class TheClass {

    private int theField= 42;

    public static void main(String[] args) throws Exception {

        TheClass c= new TheClass();

        System.out.println(c.getClass().getDeclaredField("theField").get(c));
    }
}

Answer 5

Thomas's solution is good enough for this matter.

If you want to use loop to access these three Answers, you first need to put there three into an array-like data structure ---- kind of like a principle. So loop is used for operating on an array-like data structure, not just simply to simplify typing task. And you cannot use FOR loop by simply just giving increasing-number-names to the elements.

Answer 6

Using Random function to generate number and iterating them on al using for loop

ArrayList<Integer> al=new ArrayList<Integer>(5);
    for (int i=0;i<=4;i++){

       Random rand=new Random();
        al.add(i,rand.nextInt(100));
        System.out.println(al);
    }
System.out.println(al.size());