Converting arraylist int to string

Question

I am trying to convert an arraylist of integers to an string in reverse. eg (1,2,3,4) converts to "4321".

However I am unable to get my code to work mainly due to the primitive data type error (basically why you give my an arraylist to do an array thing). My code is currently

  public String toString() {
        int n = arrList.size();
        if (n == 0)
            return "0";

        for (int i = arrList.size(); i > 0; i--);
        int nums= arrList[i];
        char myChar = (char) (nums+ (int) '0');
        String result = myChar.toString(arrList);

        return result;
}

Answer 1

• Your loop had the wrong range and it didn't do anything, since you terminated it with ;.
• In addition, arrList[i] is the way to access an element of an array. To access an element of an ArrayList you use arrList.get(i).

• Finally, you should accumulate the characters / digits somewhere before converting them to a String. I suggest a StringBuilder.

  StringBuilder sb = new StringBuilder();
  for (int i = arrList.size() - 1; i >= 0; i--) {
    int num = arrList.get(i);
    sb.append(num);
  }
  String result = sb.toString();