同时调用方法时如何向arrayList添加元素？

Question

I am doing a recursive program and I want to call a method 2 times in a row, which looks like this:

print(ArrayList<Integer> current + arr[0], Arrays.copyOfRange(arr, 1, arr.length) );
print(ArrayList<Integer> current, Arrays.copyOfRange(arr, 1, arr.length));

But it is impossible to add a value to the ArrayList like that. However, I can't use current.add() outside either, because it will mess up my second call. So is there a way to add a value to the arrayList while calling the method, or do I have to think of another way to write my code?

Answer 1

You may overload your print method like the following:

public void print(ArrayList<Integer> current, int i, int[] arr ) {
    //print whatever you want
    //then add using current.add(i)
    current.add(i)
}

then call your overloaded print() method in the first time like this:

print(current, arr[0], arr);

Answer 2

You can achieve it with following code

print(new ArrayList<Integer>(current) {{ add(arr[0]); }},
      Arrays.copyOfRange(arr, 1, arr.length) );