public class UniquePair<T extends Comparable<T>>		// class with 2 instance data of type T, T must implement
{														// Comparable so we can compare them, a UniquePair will have
	private T item1, item2;								// two different instance data, they cannot be equal
	
	public UniquePair()					// no arg constructor, both items can be null in this cas
	{
		item1=null;
		item2=null;
	}
	
	public UniquePair(T i1, T i2)		// two arg constructor, ensure items are unique or set second item to null
	{
		item1=i1;
		item2=i2;
		if(item1.compareTo(item2)==0) item2=null;
	}
	
	public T get1()						// accessors for the two instance data
	{
		return item1;
	}
	
	public T get2()
	{
		return item2;
	}
	
	public void set1(T i1)				// mutators for the two instance data, ensure the two items are unique or 
	{									// set second item to null
		item1=i1;
		if(item1.compareTo(item2)==0) item2=null;
	}

	public void set2(T i2)
	{
		item2=i2;
		if(item1.compareTo(item2)==0) item2=null;
	}	
	
	public String toString()			// toString will output item1 and item2 if T implements toString, otherwise
	{									// we get the items' addresss
		return "" + item1 + "      " + item2;
	}
}