public class DynamicArray {
   Object[] store;
   int capacity; // how many items can store
   int size; // how many items stored

   public DynamicArray() {
      store = new Object[10];
      capacity = 10;
      size = 0;
   }

   public void add(Object o) {
      // if the store has space, insert o
      if (size < capacity) {
         store[size] = o;
         size++;
      } else {
         capacity = capacity * 2; // or whatever
         Object[] newstore = new Object[capacity];
         for (int i = 0; i < size; i++) {
            newstore[i] = store[i];
         }
         store = newstore;
         store[size] = o;
         size++;
      }
   }

   public Object get(int i) {
      // check if i is within bounds;
      if ((0 <= i) && (i < size)) return store[i];
      else throw new ArrayIndexOutOfBoundsException();
   }

   public boolean remove(Object o) {
      int index = -1;
      // look for o in store
      for (int i = 0; i < size; i++) {
         if(store[i].equals(o)) {
            index = i;
            break;
         }
      }
      // if o not in store, return false
      if (index == -1) return false;
      // replace o by the next value and shift left
      for (int i = index; i < size-1; i++) { 
         store[i] = store[i+1];
      }
      size--;
      return true;
   }

   public ArrayIterator iterator() {
      return new ArrayIterator(this);
   }

   public static void main(String[] args) {
      DynamicArray myarray = new DynamicArray();
      String[] numbers = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
      for (int i = 0; i < 10; i++) {
         myarray.add(numbers[i]);
      }
      ArrayIterator it = myarray.iterator();
      while(it.hasNext()){
         System.out.print(it.next() + " ");
      }
      System.out.println();
   }

   class ArrayIterator {
      DynamicArray array;
      int current;
     
      ArrayIterator(DynamicArray d) {
         array = d;
         current = 0;
      }
    
      Object next() {
         return array.get(current++);
      }
      
      boolean hasNext() {
         return (current < array.size);
      }
   }
}