MyArrayList.java

public class MyArrayList<T> {
    private Object[] elements;
    private int size;
    private final int CAPACITY = 10;
    
    public MyArrayList() {
        // create an array with an initial size of 10
        elements = new Object[CAPACITY]; // initial capacity
        size = 0; // keeps track of the number of elements 
        // actually exist in our arraylist
    }

    public void AddStart(T elementToAdd) {
        EnsureCapacity();
        for (int i = size; i >= 0; i--) {
            elements[i + 1] = elements[i];
        }
        elements[0] = elementToAdd;
        size++;
    }

    public void AddEnd(T elementToAdd) {
        EnsureCapacity();
        elements[size] = elementToAdd;
        size++;
    }

    public void AddAtIndex(T elementToAdd, int indexToAddAt) {
        if (indexToAddAt > size || indexToAddAt < 0) {
            // add to the end if the index the user wants to add at is invalid
            AddEnd(elementToAdd);
        } else {

            EnsureCapacity();

            for (int i = size; i >= indexToAddAt; i--) {
                elements[i + 1] = elements[i];
            }
            elements[indexToAddAt] = elementToAdd;
            size++;
        }
    }

    /**
     * 
     * @param index
     * @return
     */
    public Object GetElementAtIndex(int index) {
        if (index >= size || index < 0) {
            return elements[size - 1];
        }

        return elements[index];
    }
    
    /**
     * Checks the capacity of our elements array and
     * increases its capacity if there isn't enough space
     */
    private void EnsureCapacity() {
        if (size == elements.length) {
            // increase the capacity/size of the array
            Object[] newElements = new Object[elements.length * 2];

            for (int i = 0; i < size; i++) {
                newElements[i] = elements[i];
            }

            elements = newElements;
        }
    }

    public void Print() {
        for (int i = 0; i < size; i++) {
            System.out.print(elements[i] + " ");
        }

        System.out.println();
    }

    public void DeleteAtStart() {
        DeleteAtIndex(0);
    }

    public void DeleteAtEnd() {
        DeleteAtIndex(size - 1);
    }
    

    public void DeleteAtIndex(int indexOfValueToDelete) {
        if (indexOfValueToDelete < 0 || indexOfValueToDelete >= size) {
            throw new IndexOutOfBoundsException(
                    "Index " + indexOfValueToDelete + "is invalid for ArrayList of size " + size);
        }

        for (int i = indexOfValueToDelete; i < size; i++) {
            elements[i] = elements[i + 1];
        }
        size--;
    }
    
    public void ClearAll() {
        for (int i = 0; i < size; i++) {
            elements[i] = null;
        }
        size = 0;
    }

    public boolean IsEmpty() {
        return size == 0;
    }

    public int Size() {
        return size;
    }


}