/*
 * Stack.java
 *
 * Created on March 17, 2008, 10:17 AM
 *
 * To change this template, choose Tools | Template Manager
 * and open the template in the editor.
 */

package parenmatchapplet2;

/**
 *
 * @author suchenek
 */
public class Stack {
    
    
   
    private int count;
    private int capacity;
    private int capacityIncrement;
    private Object[] itemArray;
    
    /** Creates a new instance of Stack */
    public Stack() {
        count=0;
        capacity=10;
        capacityIncrement=2;
        itemArray=new Object[capacity];
    }
    
    public void push(Object newItem)
    {
        if(count==capacity) //no more space, "resize" the array up
        {
            capacity*=capacityIncrement;
            Object[] tempArray = new Object[capacity];
            System.out.println("New stack of capacity " + capacity);
            for (int i = 0; i < count; i++)
            {
                tempArray[i] = itemArray[i];
                 cnt.incr();
//                 cnt.outln(" push resize incr ");
            }
            itemArray = tempArray;
           
    }
        cnt.incr();
//insert at the end
        itemArray[count++] = newItem;
    }
    
    public Object pop()
    {
        Object itemToReturn;
     if (count==0) return null;
   
        cnt.incr();
itemToReturn=itemArray[--count];
        
        
        if ((count < capacity / capacityIncrement) &&  (10 <= capacity / capacityIncrement)) //space wasted, "resize" the array down
        {
          capacity/=capacityIncrement;
            Object[] tempArray = new Object[capacity];
            System.out.println("New stack of capacity " + capacity);
            for (int i = 0; i < count; i++)
            {
                tempArray[i] = itemArray[i];
                cnt.incr();
//                cnt.outln(" pop resize incr ");
            }
            itemArray = tempArray;  
        }
        
        return itemToReturn;
        }
      public int size()
      {
          return count;
          
      }
      
      public boolean isEmpty()
      {
          return count==0;
      }
            public int Length()
      {
          return itemArray.length;
          
      }
    }