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C# List<T>.Reverse(int index, int count) Method with Example

C# List<T>.Reverse(int index, int count) Method: In this tutorial, we will learn about the Reverse() method of List collection with its usage, syntax, and an example using C# program. By IncludeHelp Last updated : April 15, 2023

C# List<T>.Reverse(int index, int count) Method

List<T>.Reverse(int index, int count) method is used to reverse the specified elements in the list.

Syntax

void List<T>.Reverse(int index, int count);

Parameter(s)

It accepts two parameters:

• index – starting position from where we want to reverse the elements
• count – total number of elements from the index

Return Value

It returns nothing – it's returns type is void

Example

int list declaration:
List<int> a = new List<int>();

Adding elements:
a.Add(10);
a.Add(20);
a.Add(30);
a.Add(40);
a.Add(50);
    
Reversing elements:
//reverse 3 list elements from index 1
a.Reverse(1,3);
    
Output:
10 40 30 20 50

C# program to reverse specified list elements using List<T>.Reverse(int index, int count) method

using System;
using System.Text;
using System.Collections.Generic;

namespace Test {
  class Program {
    static void printList(List <int> lst) {
      //printing elements
      foreach(int item in lst) {
        Console.Write(item + " ");
      }
      Console.WriteLine();
    }

    static void Main(string[] args) {
      //integer list
      List <int> a = new List <int> ();

      //adding elements
      a.Add(10);
      a.Add(20);
      a.Add(30);
      a.Add(40);
      a.Add(50);

      if (a.Count > 0) {
        //print the list
        Console.WriteLine("list elements...");
        printList(a);
      } else {
        Console.WriteLine("list is empty");
      }

      //reverse 3 list elements from index 1
      a.Reverse(1, 3);

      //list after reversing the elements
      if (a.Count > 0) {
        Console.WriteLine("list elements after reversing elements...");
        printList(a);
      } else {
        Console.WriteLine("list is empty");
      }

      //hit ENTER to exit
      Console.ReadLine();
    }
  }
}

Output

list elements...
10 20 30 40 50
list elements after reversing elements...
10 40 30 20 50

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