Stack.java

/**
 * A linked list implementation of a stack
 *
 * @author William Fiset, william.alexandre.fiset@gmail.com
 */


public class Stack<T> implements Iterable<T> {

 private java.util.LinkedList<T> list = new java.util.LinkedList<T>();

 // Create an empty stack
 public Stack() {}

 // Create a Stack with an initial element
 public Stack(T firstElem) {
 push(firstElem);
 }

 // Return the number of elements in the stack
 public int size() {
 return list.size();
 }

 // Check if the stack is empty
 public boolean isEmpty() {
 return size() == 0;
 }

 // Push an element on the stack
 public void push(T elem) {
 list.addLast(elem);
 }

 // Pop an element off the stack
 // Throws an error is the stack is empty
 public T pop() {
 if (isEmpty()) throw new java.util.EmptyStackException();
 return list.removeLast();
 }

 // Peek the top of the stack without removing an element
 // Throws an exception if the stack is empty
 public T peek() {
 if (isEmpty()) throw new java.util.EmptyStackException();
 return list.peekLast();
 }

 // Allow users to iterate through the stack using an iterator
 @Override
 public java.util.Iterator<T> iterator() {
 return list.iterator();
 }
}