How to Perform Tree Operations in Java

In Computer Science, a tree is a data structure that can contain elements of an arbitrary type. The tree supports diverse retrieval methods, such as finding the element with a given value, or the elements smaller than a given value, or retrieving all elements in order. You can use the TreeSet class (pre-defined in the Java standard class libraries) to perform tree operations in your Java code.

Instructions

1. Insert the following line at the beginning of your Java code:

   import java.util.*;

2. Populate a TreeSet object by declaring it, then inserting some elements--as in the following sample code:

   TreeSet <Integer>myTree = new TreeSet<Integer>;

   myTree.add(9);

   myTree.add(2);

   myTree.add(-1);

   The sample tree has Integer elements (you can use any Java reference type): 9, 2 and -1.

3. Determine if an element is present in the TreeSet, as in the following sample code:

   myTree.contains(new Integer(4));

   The sample expression will evaluate to "false", as the object has not been added to the tree.

4. Remove an element known to be in the tree, as in the following sample code:

   Integer myFour = new Integer(4);

   myTree.add(myFour);

   myTree.remove(myFour);

References

• Oracle: Java: Class TreeSet