Number of elements in HashSet in C#?

To get the number of elements in HashSet in C#, the code is as follows −

Example

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main() {
      HashSet<int> set1 = new HashSet<int>();
      set1.Add(25);
      set1.Add(50);
      set1.Add(75);
      set1.Add(100);
      set1.Add(125);
      set1.Add(150);
      Console.WriteLine("Elements in HashSet1");
      foreach(int val in set1) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Number of elements in HashSet1 = "+set1.Count);
      HashSet<int> set2 = new HashSet<int>();
      set2.Add(30);
      set2.Add(60);
      set2.Add(100);
      set2.Add(150);
      set2.Add(200);
      set2.Add(250);
      Console.WriteLine("Elements in HashSet2");
      foreach(int val in set2) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Number of elements in HashSet2 = "+set2.Count);
      Console.WriteLine("Do they share common elements? "+set1.Overlaps(set2));
      Console.WriteLine("Does HashSet1 has element 60? "+set1.Contains(60));
      Console.WriteLine("Does HashSet2 has element 60? "+set2.Contains(60));
   }
}

Output

This will produce the following output −

Elements in HashSet1
25
50
75
100
125
150
Number of elements in HashSet1 = 6
Elements in HashSet2
30
60
100
150
200
250
Number of elements in HashSet2 = 6
Do they share common elements? True
Does HashSet1 has element 60? False
Does HashSet2 has element 60? True

Example

Let us see another example −

 Live Demo

using System;
using System.Collections.Generic;
public class Demo {
   public static void Main() {
      HashSet<string> set1 = new HashSet<string>();
      set1.Add("AB");
      set1.Add("CD");
      set1.Add("EF");
      set1.Add("AB");
      set1.Add("IJ");
      set1.Add("KL");
      set1.Add("EF");
      set1.Add("OP");
      Console.WriteLine("Elements in HashSet1");
      foreach(string val in set1) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Number of elements in HashSet1 = "+set1.Count);
      HashSet<string> set2 = new HashSet<string>();
      set2.Add("EF");
      set2.Add("KL");
      Console.WriteLine("Number of elements in HashSet2 = "+set2.Count);
      Console.WriteLine("Elements in HashSet2");
      foreach(string val in set2) {
         Console.WriteLine(val);
      }
      Console.WriteLine("Is set1 a superset of set2? "+set1.IsSupersetOf(set2));
   }
}

Output

This will produce the following output −

Elements in HashSet1
AB
CD
EF
IJ
KL
OP
Number of elements in HashSet1 = 6
Number of elements in HashSet2 = 2
Elements in HashSet2
EF
KL
Is set1 a superset of set2? True