Difference between Array and ArrayList

Question

Ashutosh Kumar Verma · Answer

C# Array vs ArrayList
Arrays and ArrayLists are used to store aggregated data but have many differences in features and functionality
Syntax-
Array
int[] arrayName = new int[size];
ArrayListand 
ArrayList arrayListName = new ArrayList();
There are several differences between Array and ArrayList as follows,
and 
Type Safety
Arrays are type-safe, meaning you specify the type of elements the array can contain when you declare them. Once declared, an array can only contain elements of its specified type.and ArrayLists are not type-safe; You can contain elements of any data type. These variables can cause runtime errors if you try to store incompatible types in an ArrayList.
and 
Resizing
Arrays have a fixed size when created. If you need to change the size of an array, you must create a new array of the desired size and copy the elements from the old array to the new array.ArrayLists dynamically resize themselves as needed. They automatically grow or shrink in proportion to the amount of material added or subtracted.
and 
Performance
Arrays typically offer better performance than ArrayLists because they have a fixed size and direct access to elements via indexes.ArrayList- If capacity needs to change, there may be some performance overhead due to resizing the ArrayLists process.
and 
Usage
Array- If the size of the collection is already known, the arrays are likely to be used extensively and not modified.ArrayLists are used when column size can change or when element type flexibility is needed.
and 
Length Property vs. Count Property
Arrays use the Length property to get the number of elements in an Array.
int length = arrayName.Length;
ArrayLists use the Count property to get the number of elements in an ArrayList.
int count = arrayListName.Count;
and 
Element Access
Arrays provide direct access to elements through indexing.
elementType element = arrayName[index];
ArrayLists Provides access to objects using the ArrayList[index] syntax or through methods such as
Add, Insert, and Remove.
object element = arrayListName[index];
and 
Example-and 
Arrayand 
using System;
class Program
{
 static void Main()
 {
 // Declaring and initializing an array
 int[] numbers = { 1, 2, 3, 4, 5 };
 // Accessing elements from array
 Console.WriteLine("First element: " + numbers[0]);
 Console.WriteLine("Second element: " + numbers[1]);
 // Iterating through loop from array
 Console.WriteLine("
Array elements are:");
 foreach (int number in numbers)
 {
 Console.WriteLine(number);
 }
 Console.ReadLine();
 }
}
Output-
First element: 1
Second element: 2
Array elements are:
1
2
3
4
5
ArrayList
using System;
using System.Collections;
class Program
{
 static void Main()
 {
 // Creating an ArrayList
 ArrayList arrayList = new ArrayList();
 // Adding elements in the ArrayList
 arrayList.Add("Apple");
 arrayList.Add("Banana");
 arrayList.Add("Orange");
 // Accessing elements from the ArrayList
 Console.WriteLine("First element: " + arrayList[0]);
 Console.WriteLine("Second element: " + arrayList[1]);
 // Iterating through the loop from ArrayList
 Console.WriteLine("
ArrayList elements:");
 foreach (object item in arrayList)
 {
 Console.WriteLine(item);
 }
 Console.ReadLine();
 }
}
Output-and 
First element: Apple
Second element: Banana
ArrayList elements:
Apple
Banana
Orange
In summary, Arrays work well and are suitable for fixed-size collections of known types, while ArrayLists offer
flexibility and dynamic resizability, making them suitable for situations where collection size may change or where type flexibility is important However, with the introduction of generics in C# (e.g.,
Listandlt;T>), ArrayLists are rare in modern codebases.
and 
Also, Read: Dictionary vs Hashtable in C#

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Difference between Array and ArrayList

Sandra Emily

1 Answers

C# Array vs ArrayList

Type Safety

Resizing

Performance

Usage

Length Property vs. Count Property

Element Access

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