Design a data structure IntSet that can hold a set of integers. Hide the private implementation: a binary search tree of Integer objects. Provide the following methods:

Complete the following file:

IntSet.java

Use the following file:

IntSetTester.java

/**
   A test program for the IntSet class.
*/
public class IntSetTester
{  
   public static void main(String[] args)
   {  
      IntSet s = new IntSet();
      s.add(2);
      s.add(3);
      s.add(7);
      s.add(5);
      s.add(9);
      s.add(7);
      s.remove(9);
      s.print();
      System.out.println("Expected: 2 3 5 7");
      System.out.println(s.find(7));
      System.out.println("Expected: true");
      System.out.println(s.find(9));
      System.out.println("Expected: false");
   }
}