// A class that implements the IntList interface stores a list of integers.
// The interface just specifies the methods that a list must have,
// not how they are implemented (that is up to the class authors).
//
// Clients can declare variables and parameters of type IntList
// so that the same code can interact with any type of list.
// This idea is called polymorphism.

public interface List<E> {
    public void add(E value);
    public void add(int index, E value);
    public void clear();
    public E get(int index);
    public int indexOf(E value);
    public boolean isEmpty();
    public void remove(int index);
    public void set(int index, E value);
    public int size();
}