Union of two HashSet in C#

Let us see an example to get the Union of two HashSet

Example

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(){
      HashSet<int> set1 = new HashSet<int>();
      set1.Add(100);
      set1.Add(200);
      set1.Add(300);
      set1.Add(400);
      set1.Add(500);
      set1.Add(600);
      Console.WriteLine("HashSet1 elements...");
      foreach(int ele in set1){
         Console.WriteLine(ele);
      }
      HashSet<int> set2 = new HashSet<int>();
      set2.Add(100);
      set2.Add(200);
      set2.Add(300);
      set2.Add(400);
      set2.Add(500);
      set2.Add(600);
      Console.WriteLine("HashSet2 elements...");
      foreach(int ele in set2){
         Console.WriteLine(ele);
      }
      Console.WriteLine("Union...");
      set1.UnionWith(set2);
      foreach(int ele in set1){
         Console.WriteLine(ele);
      }
   }
}

Output

This will produce the following output −

HashSet1 elements...
100
200
300
400
500
600
HashSet2 elements...
100
200
300
400
500
600
Union...
100
200
300
400
500
600

Example

Let us now see another example −

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main(){
      HashSet<int> set1 = new HashSet<int>();
      set1.Add(100);
      set1.Add(200);
      set1.Add(300);
      set1.Add(400);
      set1.Add(500);
      set1.Add(600);
      Console.WriteLine("HashSet1 elements...");
      foreach(int ele in set1){
         Console.WriteLine(ele);
      }
      HashSet<int> set2 = new HashSet<int>();
      set2.Add(100);
      set2.Add(250);
      set2.Add(300);
      Console.WriteLine("HashSet2 elements...");
      foreach(int ele in set2){
         Console.WriteLine(ele);
      }
      Console.WriteLine("Union...");
      set1.UnionWith(set2);
      foreach(int ele in set1){
         Console.WriteLine(ele);
      }
   }
}

Output

This will produce the following output −

HashSet1 elements...
100
200
300
400
500
600
HashSet2 elements...
100
250
300
Union...
100
200
300
400
500
600
250