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Lesson 3115 min read

Structs

Learn how structs differ from classes in C# and when to use a value type over a reference type.

What is a Struct?

A struct looks very similar to a class — it can have fields, properties, and methods — but it is a value type, not a reference type. `int`, `double`, `bool`, and `DateTime` are all actually structs under the hood.

struct Point
{
    public int X;
    public int Y;


    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }
}


Point p1 = new Point(1, 2);
Point p2 = p1; // this COPIES the struct
p2.X = 99;


Console.WriteLine(p1.X); // 1 — unaffected
Console.WriteLine(p2.X); // 99
Output

Click Run to see what this code prints.

Structs vs Classes

struct

  • Value type — copied on assignment
  • Stored on the stack (usually)
  • No inheritance (except interfaces)
  • Best for small, simple data

class

  • Reference type — shared on assignment
  • Stored on the heap
  • Supports full inheritance
  • Best for complex objects with identity

When to Use a Struct

Reach for a struct when modeling a small, immutable-feeling value where copying is cheap and expected — like a 2D point, an RGB color, or money amount. Use a class for anything larger or where shared identity matters.

FAQs

No — structs cannot inherit from another struct or class (though they can implement interfaces), and nothing can inherit from a struct.

Summary

  • Structs are value types, copied on assignment rather than shared by reference.
  • Most built-in "primitive" types in C# are actually structs.
  • Use structs for small, simple values; classes for everything else.
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Collections