/**
 * Simple Stack interface.
 * @author bdb52
 * @version 1.0
 */
public interface Stack<T> {

    /**
     * Adds something to the top of the stack.
     * @param obj - the object to be added.
     * @return the object parameter.
     */
    public T push(T obj);

    /**
     * Returns a reference to the top of the stack.
     * Does not modify the stack.
     * @return a reference to the top of the stack.
     */
    public T peek();

    /**
     * Removes the top element from the stack.
     * @return a reference to the element that was on the top of the stack.
     */
    public T pop();

    /**
     * Determines if the stack is empty.
     * @return true if the stack is empty.
     */
    public boolean empty();
}