What is the difference between Array and List?

In C# Array and List<T> are different data structures with different behaviors and purposes:

• Array — fixed size, declared with a specific length that cannot be changed after creation. Faster in performance when accessing elements, as it is a simple block of memory.

• List<T> — a dynamic list from the System.Collections.Generic namespace. Its size can change during runtime (automatically expands when adding elements). Provides convenient methods for adding, removing, searching, and sorting elements.

Example:

int[] array = new int[3] {1, 2, 3};
// array[3] = 4; // Error, index out of range

List<int> list = new List<int>() {1, 2, 3};
list.Add(4); // List size increased

Summary:

• Use Array when the size is fixed and performance is important.
• Use List<T> when a dynamic size and convenient collection methods are needed.