ArrayList Yan

public class ArrayList {
    //Private Variables can not be public! and should not have setters or getters
    private int size;
    private int[] arr;

    public ArrayList() {
        size = 0;
        arr = new int[1];
    }
    //Array Lists public methods
    public void add(int value, int index){
        if(index > size) return;
        makeRoom();
        if(index != size)
            moveOneUp(index);
        arr[index] = value;
        size++;

    }
    public void add(int value){
        add(value, size);
    }
    public void remove(int index){
        if(size > 0) {
            for (int i = index; i < size; i++) {
                int tempNum = arr[i];
                arr[i] = arr[i + 1];
                arr[i + 1] = tempNum;
            }
            size--;
        }
    }
    public int get(int index){
        if(index >= size) return -1;
        return arr[index];
    }
    public void set(int value, int index){
        if(index >= size) return;
        arr[index] = value;
    }
    public int size(){
        return size;
    }
    public int indexOf(int value){
        for (int i = 0; i < size; i++) {
            if(value == arr[i]) return i;
        }
        return -1;
    }
    public void clear(){
        size = 0;
    }
    public int[] toArray(){
        int[] tempArr = new int[size];
        for (int i = 0; i < size; i++) {
            tempArr[i] = arr[i];
        }
        return tempArr;
    }

    //Private Class methods for class usage, can not be public!
    private void makeRoom() {
        if(size == arr.length){
            int[] temp = new int[size*2];
            for (int i = 0; i < size; i++) {
                temp[i] = arr[i];
            }
            arr = temp;
        }
    }
    private void moveOneUp(int index) {
        int[] tempArr = new int[arr.length];
        for (int i = 0; i < size; i++) {
            if(i >= index)
                tempArr[i+1] = arr[i];
            else
                tempArr[i] = arr[i];
        }
        arr = tempArr;

    }
}