HashSet in C# eliminates duplicate strings or elements in an array.In C#, it is an optimized set collection.Let us see an example to remove duplicate strings using C# HashSet −Exampleusing System; using System.Collections.Generic; using System.Linq; class Program {    static void Main() {       string[] arr1 = {          "one",          "two",          "two",          "one",          "three"       };       Console.WriteLine(string.Join(",", arr1));       // HashSet       var h = new HashSet(arr1);       // eliminates duplicate words       string[] arr2 = h.ToArray();       Console.WriteLine(string.Join(",", arr2));    } }To declare HashSet.var h = new HashSet

Firstly, set the original array −int[] arr = { 1, 2,3 }; // Original Array Console.WriteLine("Original Array= "); fo            reach (int i in arr) {    Console.WriteLine(i); }Now, use the Array.reverse() method to reverse the array −Array.Reverse(arr);The following is the complete code to reverse an array in C# −Exampleusing System; class Demo {    static void Main() {       int[] arr = { 9, 32, 87, 45, 77, 56 };       // Original Array       Console.WriteLine("Original Array= ");       foreach (int i in arr) {          Console.WriteLine(i);       }       // Reverse Array       Array.Reverse(arr);       Console.WriteLine("Reversed Array= ");       foreach (int j in arr) {          Console.WriteLine(j);       }       Console.ReadLine();    } }

Java has a final keyword, but C# does not have its implementation. For the same implementation, use the sealed keyword.With sealed, you can prevent overriding of a method. When you use sealed modifiers in C# on a method, then the method loses its capabilities of overriding. The sealed method should be part of a derived class and the method must be an overridden method.The following example won’t allow you to override the method display() because it has a sealed modifier for the ClassTwo derived class.ClassOne is our base class, whereas ClassTwo and ClassThree are derived classes −Exampleclass ClassOne {   ... Read More

Arrays were a pointer to an address in memory of the index. This index was the 1st element of the array. Here, the index is like an offset and the concept even before C language originated.Let’s say your array elements begins from 0Xff000 and has 5 elements like {35, 23, 67, 88, 90}. Therefore, you array in memory would be like the following because int is stored using 4 bytes.0Xff000 has 35 0Xff004 has 23 0Xff008 has 67 0Xff012 has 88 0Xff016 has 90That would mean when the array is accessed, zero offsets would be index 0.Let us further see ... Read More

Tuple comparison came after C# 7.3.Easily compare two tuples using the equality operator in C#.Let’s say we have two tuples −var one = (x: 1, y: 2); var two = (p: 1, 2: 3, r: 3, s:4);To compare them, just use the == operator −if (one == two) Console.WriteLine("Both the tuples are same (values are same).");Let use see the code −Examplevar one = (x: 1, y: 2); var two = (p: 1, 2: 3, r: 3, s:4); if (one == two) Console.WriteLine("Both the tuples are same (values are same)."); lse Console.WriteLine("Both the tuples values are not same.");

While declaring a method, if you are not sure of the number of arguments passed as a parameter, then use the C# param arrays.The following is the complete example to learn how to implement param in C# −Exampleusing System; namespace Program {    class ParamArray {       public int AddElements(params int[] arr) {          int sum = 0;                  foreach (int i in arr) {             sum += i;          }          return sum;       }    }    class Demo {       static void Main(string[] args) {          ParamArray app = new ParamArray();          int sum = app.AddElements(300, 250, 350, 600, 120);          Console.WriteLine("The sum is: {0}", sum);          Console.ReadKey();       }    } }

Internal keyword allows you to set internal access specifier.Internal access specifier allows a class to expose its member variables and member functions to other functions and objects in the current assembly.Any member with internal access specifier can be accessed from any class or method defined within the application in which the member is defined.Exampleusing System; namespace RectangleApplication {    class Rectangle {       internal double length;       internal double width;       double GetArea() {          return length * width;       }       public ... Read More

There are two types of collections in C#: non-generic collections and generic collections.Generics in C#Generic collections hold elements of same datatypes.For example −ListDictionaryHashsetDictionary − Dictionary is a collection of keys and values in C#. Dictionary is included in the System.Collection.Generics namespace.Hashset − HashSet in C# eliminates duplicate strings or elements in an array.In C#, it is an optimized set collection.Non-Generics in C#Non-generic collections hold elements of different datatypes.The following are the non-generic collections: ArrayList, BitArray.ArrayList − It represents ordered collection of an object that can be indexed individually. ArrayList is an alternative to an array. However, unlike array you ... Read More

Numeric promotion is the promotion of smaller types to larger types like short to int.In the below example, we have seen a numeric promotion in Conditional Expression.The short types are automatically promoted to larger type int.Exampleusing System; class Program {    static void Main() {       short val1 = 99;       int val2;       val2 = (val1 == 1) ? 100 : 30;       Console.WriteLine(val2);    } }OutputAbove, we have used a conditional expression that automatically promoted to int −val2 = (val1 == 1) ? 100 : 30;Here, val2 is an int and val is a short.

For multiple-base conversions, set a variable and add the base you want to calculate.Here, for our example, I have set the variable baseNum as 2 −int baseNum = 2;In the same way, if you want base 8, then set the above as −int baseNum = 2; You can also get the above variable value as user input.After getting the value, set a stack and get the values −Stack s = new Stack(); do { s.Push(n % baseNum); n /= baseNum; } while (n != 0);After using the stack, pop out the elements. That would give you the result.Let’s say the ... Read More