public class Vector_Integer_ {

    private Integer[] entries;
    private int size = -1;  // the current number of entries

    public Vector_Integer_() {
	entries = new Integer[1];
	size = 0;
    }

    public void add(Integer i) {
	if (size >= entries.length) 
	    resize(2*entries.length);
	entries[size++] = i;
    }

    public Integer elementAt(int offset) {
	return entries[offset];
    }

    public int size() { return size;}

    private void resize(int n) {

	Integer[] newEntries = new Integer[n];
	System.arraycopy(entries,0,newEntries,0,entries.length);
	entries = newEntries;
    }

}