Arrays and ArrayLists in C# Programming

In C# programming, arrays and ArrayLists are used to store collections of data. While arrays are fixed in size, ArrayLists are dynamic and can grow or shrink as needed.

Arrays in C#

An array is a collection of elements of the same type. Arrays have a fixed size and are declared using square brackets.

Step-by-Step Example: Using Arrays

    using System;
   class Program {
        static void Main() {
            // Declare and initialize an array
            int[] numbers = { 10, 20, 30, 40, 50 };
           // Access elements
            Console.WriteLine("First element: " + numbers[0]);
            Console.WriteLine("Second element: " + numbers[1]);
           // Iterate through the array
            Console.WriteLine("All elements:");
            for (int i = 0; i < numbers.Length; i++) {
                Console.WriteLine(numbers[i]);
            }
        }
    }
        

Output:

First element: 10
Second element: 20
All elements:
10
20
30
40
50

Key Points About Arrays

• Arrays are zero-indexed.
• They have a fixed size defined at the time of initialization.
• You can use the Length property to determine the number of elements.

ArrayLists in C#

An ArrayList is a dynamic collection that can hold elements of any type. It is part of the System.Collections namespace.

Step-by-Step Example: Using ArrayLists

    using System;
    using System.Collections;
   class Program {
        static void Main() {
            // Create an ArrayList
            ArrayList list = new ArrayList();
           // Add elements
            list.Add(10);
            list.Add(20);
            list.Add("Hello");
            list.Add(40.5);
           // Access elements
            Console.WriteLine("First element: " + list[0]);
            Console.WriteLine("Third element: " + list[2]);
           // Iterate through the ArrayList
            Console.WriteLine("All elements:");
            foreach (var item in list) {
                Console.WriteLine(item);
            }
        }
    }
        

Output:

First element: 10
Third element: Hello
All elements:
10
20
Hello
40.5

Key Points About ArrayLists

• ArrayLists can store elements of different types.
• They are dynamic and can grow or shrink in size.
• Performance can be slower than arrays due to boxing and unboxing when working with value types.

Comparison of Arrays and ArrayLists

Conclusion

Arrays and ArrayLists are essential data structures in C# for managing collections. Arrays are best for fixed-size, type-specific data, while ArrayLists provide flexibility with dynamic sizing and mixed types. Choose the one that best fits your application's needs.