C# | Adding an element to the List

List.Add(T) Method is used to add an object to the end of the List.

Properties of List:

  • It is different from the arrays. A list can be resized dynamically but arrays cannot.
  • List class can accept null as a valid value for reference types and it also allows duplicate elements.
  • If the Count becomes equals to Capacity then the capacity of the List increases automatically by reallocating the internal array. The existing elements will be copied to the new array before the addition of the new element.
  • If the Count is less than Capacity then this method is an O(1) operation. If the capacity needs to be increased to accommodate the new element then this method becomes an O(n) operation.

Syntax:

public void Add (T item);

Parameter:

item: Specified object which is to be added to the end of the List of type System.Object.



Below programs illustrate how to add an element in List:

Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# program to add element in List<T>
using System;
using System.Collections.Generic;
  
class Geeks {
  
    // Main Method
    public static void Main(String[] args)
    {
  
        // Creating a List of integers
        List<int> firstlist = new List<int>();
  
        // adding elements in firstlist
        for (int i = 4; i < 10; i++) {
            firstlist.Add(i * 2);
        }
  
        // Displaying elements of firstlist
        // by using foreach loop
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }
    }
}

chevron_right


Output:

8
10
12
14
16
18

Example 2:

filter_none

edit
close

play_arrow

link
brightness_4
code

// C# program to add element in List<T>
using System;
using System.Collections.Generic;
  
class Geeks {
  
    // Main Method
    public static void Main(String[] args)
    {
  
        // Creating a List of integers
        List<int> firstlist = new List<int>();
  
        // adding elements in firstlist
        firstlist.Add(1);
        firstlist.Add(2);
        firstlist.Add(3);
        firstlist.Add(4);
  
        // Adding some duplicate
        // elements in firstlist
        firstlist.Add(3);
        firstlist.Add(4);
  
        // Displaying elements of firstlist
        // by using foreach loop
        foreach(int element in firstlist)
        {
            Console.WriteLine(element);
        }
    }
}

chevron_right


Output:

1
2
3
4
3
4

Reference:



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.