package rebelsky.linear;

import java.lang.reflect.Array;

/**
 * An array-based implementation of queues.
 *
 * @author Samuel A. Rebelsky
 * @author Margaret Louisa Poythress
 * @au
 * @version 1.0 of October 2004.
 */
public class LABS
	implements Stack
{
// +--------+--------------------------------------------------
// | Fields |
// +--------+

	/** The index of the "last" thing. */
	int lastThing;
	
	/** The stuff actually in the stack. */
	Object[] contents;

// +--------------+--------------------------------------------
// | Constructors |
// +--------------+
	
	public LABS()
	{
		this.lastThing = -1;
		this.contents = new Object[2];
	} // LABS()

// +---------+-------------------------------------------------
// | Methods |
// +---------+

	public void put(Object addMe)
	{
		if (lastThing+1 >= contents.length){
			// Make a new array that's twice as big
			Object[] arrayNew = new Object[contents.length*2];
			// Copy everything into the new array
			for (int i = 0; i < contents.length; i++) {
				// Set the ith value of arrayNew to the ith value of contents.
				arrayNew[i] = contents[i];
				// java.lang.reflect.Array.set(arrayNew, i, java.lang.reflect.Array.get(contents, i));
				// Array.set(arrayNew, i, Array.get(contents, i));
			}
			// Make that new array our countents
			this.contents = arrayNew;
			// Add the value
		}
		this.contents[this.lastThing+1] = addMe;
		this.lastThing += 1;
	} // put(Object)

	public Object get()
	{
		Object returnMe = this.contents[this.lastThing];
		this.contents[this.lastThing] = null; // Actually remove it.
		this.lastThing -= 1;
		return returnMe;
	} // get()

	public Object peek()
	{
		return this.contents[this.lastThing];
	} // peek()

	public boolean isEmpty()
	{
		return this.lastThing == -1;
	} // isEmpty()

} // LABS()