Array in C# vs. ArrayList in C# — What's the Difference?
Edited by Tayyaba Rehman — By Fiza Rafique — Published on January 2, 2024
Array in C# is fixed-size and strongly typed; ArrayList in C# is dynamic and stores objects.
Difference Between Array in C# and ArrayList in C#
Table of Contents
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Key Differences
Array in C# is a collection of elements, all of the same type, stored in contiguous memory locations. The size of the Array in C# is determined at the time of its declaration and cannot be changed afterwards. ArrayList in C#, on the other hand, belongs to the System.Collections namespace and is dynamic, allowing elements to be added or removed during runtime.
In terms of type safety, Array in C# is strongly typed, meaning it can only store elements of a specific data type. This ensures type safety but can limit flexibility. Conversely, ArrayList in C# can store any object type, making it more flexible but potentially less type-safe, as type-casting is often required when retrieving items.
Performance-wise, Array in C# typically offers faster access times because of its fixed size and type safety. However, ArrayList in C# may have overheads associated with its dynamic nature and boxing/unboxing operations, which can affect its performance.
Memory utilization is another area of difference. Array in C# has a fixed size, so memory is allocated at the time of declaration. ArrayList in C#, being dynamic, can grow as needed, but may lead to more memory fragmentation due to periodic resizing.
For operations like adding or removing elements, Array in C# can be cumbersome since its size is immutable. On the flip side, ArrayList in C# provides methods like Add() and Remove() that make these operations relatively straightforward.
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Comparison Chart
Size
Fixed
Dynamic
Type Safety
Strongly typed
Stores any object type
Performance
Typically faster
Overheads due to dynamic nature and boxing
Memory Utilization
Memory set at declaration
Can grow, may lead to fragmentation
Methods
Limited methods for manipulation
Rich methods like Add(), Remove()
Compare with Definitions
Array in C#
A fixed-size collection of elements of the same type.
Int[] numbers = new int[5]; creates an integer Array in C# with 5 elements.
ArrayList in C#
A dynamic collection that can grow or shrink during runtime.
The ArrayList in C# is versatile due to its ability to resize.
Array in C#
A data structure storing elements in contiguous memory locations.
The Array in C# ensures quick access due to its contiguous memory allocation.
ArrayList in C#
A list allowing indexed access and dynamic size adjustments.
When unsure about the number of elements, use ArrayList in C#.
Array in C#
A collection with a predetermined size.
Once initialized, the size of an Array in C# cannot change.
ArrayList in C#
A data structure offering methods for easy manipulation.
With methods like Add() and Remove(), ArrayList in C# simplifies data manipulation.
Array in C#
A strongly typed collection in C#.
When declaring an Array in C#, you must specify its data type.
ArrayList in C#
A member of the System.Collections namespace.
To use ArrayList in C#, you must reference the System.Collections namespace.
Array in C#
A fundamental data structure for collection storage in C#.
Every C# developer should be familiar with using Array in C#.
ArrayList in C#
A collection that can store elements of any object type.
The ArrayList in C# can hold integers, strings, and custom objects.
Common Curiosities
How is an ArrayList in C# different from an Array?
ArrayList in C# is dynamic, can hold any object type, and provides methods for manipulation.
Is Array in C# more performance-efficient than ArrayList in C#?
Typically, Array in C# is faster due to its fixed size and type safety.
How can I add elements to an ArrayList in C#?
Use the Add() method to add elements to an ArrayList in C#.
Which is more type-safe: Array in C# or ArrayList in C#?
Array in C# is more type-safe as it's strongly typed, while ArrayList in C# stores any object.
How do I remove an element from an ArrayList in C#?
Use the Remove() or RemoveAt() methods with ArrayList in C#.
Can Array in C# hold elements of different data types?
No, an Array in C# can only hold elements of its declared type.
What is an Array in C#?
An Array in C# is a fixed-size, strongly typed collection of elements.
Can the size of an Array in C# be changed after declaration?
No, the size of an Array in C# is fixed once declared.
Can I store custom objects in an ArrayList in C#?
Yes, ArrayList in C# can store any object type, including custom ones.
How do I declare an Array in C#?
Declare an Array in C# by specifying its type and size, like int[] arr = new int[10];.
How can I access an element in an Array in C#?
Use the index, like arr[3], to access the 4th element in an Array in C#.
Do I need to import a specific namespace to use ArrayList in C#?
Yes, to use ArrayList in C#, you should import the System.Collections namespace.
Is boxing/unboxing a concern with ArrayList in C#?
Yes, ArrayList in C# may involve boxing/unboxing, impacting performance.
Why choose Array in C# over ArrayList in C#?
Array in C# offers type safety, faster access, and can be preferred when size is known.
How can I increase the capacity of an ArrayList in C#?
ArrayList in C# automatically resizes, but you can manually set capacity using the Capacity property.
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Written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
Edited by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
