java.util.TreeSet.add() Method

Description

The add(Object o) method is used to add the specified element to this set if it is not already present.

Declaration

Following is the declaration for java.util.TreeSet.add() method.

public boolean add(Object o)

Parameters

• o--This is the element to be added to this set.

Return Value

The method call returns true if the set did not already contain the specified element.

Exception

• ClassCastException--It throws the exception if the specified object cannot be compared with the elements currently in the set.

Example

The following example shows the usage of java.util.TreeSet.add() method.

package com.tutorialspoint;

import java.util.Iterator;
import java.util.TreeSet;

public class TreeSetDemo {
   public static void main(String[] args) {
     // creating a TreeSet 
     TreeSet <Integer>treeadd = new TreeSet<Integer>();
     
     // adding in the tree set
     treeadd.add(12);
     treeadd.add(13);
     treeadd.add(14);
     treeadd.add(15);
     
     // create an iterator
     Iterator iterator;
     iterator = treeadd.iterator();
     
     // displaying the Tree set data
     System.out.print("Tree set data: ");     
     while (iterator.hasNext()){
        System.out.print(iterator.next() + " ");
     }
   }   
}

Let us compile and run the above program, this will produce the following result.

Tree set data: 12 13 14 15