When to use Struct over Class in C#

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Ravi Vishwakarma · Answer

In C#, both structs and classes are used to define types, but they have distinct differences and are used in different scenarios.and 
Key Differences Between Structs and Classes
Value Type vs. Reference Type:
Structs are value types and are stored on the stack. When you assign a struct to a new variable, a copy of the value is made.Classes are reference types and are stored on the heap. When you assign a class to a new variable, you are copying the reference to the same object.
Memory Management:
Structs are automatically deallocated when they go out of scope.Classes are managed by the garbage collector, which means their lifetime is controlled by the garbage collector.
Inheritance:
Structs do not support inheritance (they cannot inherit from another struct or class, nor can they be a base for other structs or classes). However, they can implement interfaces.Classes support inheritance, allowing for more flexible and reusable code.
Default Constructor:
Structs cannot have an explicit parameterless constructor; they always have an implicit default constructor that initializes all members to their default values.Classes can have explicit parameterless constructors.
and 
When to Use Structs
Small Data Structures: Use structs for small, lightweight objects that represent simple data structures. Typically, a struct should not have more than a few fields.Immutability: Structs are best suited for immutable types, where the data they hold does not change after creation. Immutable types help avoid unintended side effects and make your code easier to reason about.Performance Considerations: Use structs when performance is critical, and you want to avoid the overhead of heap allocation and garbage collection. Since structs are stored on the stack, they can be more efficient for small, short-lived data.No Need for Polymorphism: Use structs when you do not need the features of inheritance and polymorphism. Since structs do not support inheritance, they are not suitable if you need to extend or modify behavior through derived types.
Example of Using a Struct
public struct Point
{
    public int X { get; }
    public int Y { get; }
    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }
    public override string ToString() => $"({X}, {Y})";
}
class Program
{
    static void Main()
    {
        Point p1 = new Point(10, 20);
        Point p2 = p1;  // p2 is a copy of p1
        p2 = new Point(30, 40);  // This does not affect p1
        Console.WriteLine(p1);  // Output: (10, 20)
        Console.WriteLine(p2);  // Output: (30, 40)
    }
}
When to Use Classes
Complex Data Structures: Use classes for complex data structures that require methods, properties, and events.Large Objects: Classes are better suited for large objects or objects that need to be shared and modified across different parts of your application.Inheritance and Polymorphism: Use classes when you need inheritance and polymorphism to create flexible and reusable code.Managed Lifetime: Use classes when you need objects with a managed lifetime and garbage collection.
Example of Using a Class
public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public Person(string firstName, string lastName)
    {
        FirstName = firstName;
        LastName = lastName;
    }
    public override string ToString() => $"{FirstName} {LastName}";
}
class Program
{
    static void Main()
    {
        Person person1 = new Person("Alice", "Smith");
        Person person2 = person1;  // person2 references the same object as person1
        person2.FirstName = "Bob";  // This affects person1 as well
        Console.WriteLine(person1);  // Output: Bob Smith
        Console.WriteLine(person2);  // Output: Bob Smith
    }
}
In summary, use structs for small, simple, and
immutable data structures where value semantics are desired. Use classes for more
complex data structures, where you need reference semantics,
inheritance, and polymorphism.

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When to use Struct over Class in C#

Steilla Mitchel

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Key Differences Between Structs and Classes

When to Use Structs

When to Use Classes

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