Here is the code we wrote today (more or less; there were slight variations between classes):
public class List { private int[] vals; //items in the list private int num; //number of list items public List() { //create an empty list this.vals = new int[5]; this.num = 0; } public void append(int item) { //add item to the end vals[num] = item; num++; } public int size() { return num; } }