C# Struct vs Class: Key Differences 🔑

A C# struct is a value type with the main purpose of storing data in a structured way. Classes are more about defining behavior, while structs give us a way to structure data.

Structs are stored on the stack and they cannot be null. Unlike classes, structs do not support inheritance. Also, you do not need to use the new keyword to create a struct.

So, structs:

• Are value types
• Do not support inheritance
• Can implement interfaces
• Are stack-allocated
• Cannot be null

Structs are faster than classes when storing small amounts of data (under 16 bytes).

It's because of the way they allocate memory:

1. Classes are allocated on the heap and garbage-collected.
2. Structs are allocated on the stack or inline and deallocated when the stack unwinds or the containing type is deallocated.

Structs being stored on stack means cheaper allocations and deallocations than classes.

However, classes may be faster than structs when working with large objects or when the object needs to be frequently boxed and unboxed.

When we box a value, it creates a new object on the heap and copies the value into it. The new allocation might lead to performance degradation. So if you decide to use structs, pay attention to boxing.

Use ref's to improve performance

To improve the performance of structs we can pass them by reference using the ref keyword. That way, when we pass a struct to a method, we pass a reference rather than a copy.