Hello all, I am a beginner and have a question: In C#, when would you choose struct over class, and what are the performance implications of using structs in .NET?
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Hello all, I am a beginner and have a question: In C#, when would you choose struct over class, and what are the performance implications of using structs in .NET?
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Sangeetha SPosted Oct 17, 2025, 4:22 AM
The type represents a small, simple value:
Point,Color,DateTime,Complex, etc.It has value semantics:
It is immutable:
It doesn’t require inheritance or polymorphism:
System.ValueType) and cannot be abstract or virtual.You want to avoid heap allocation:
Sudarshan HajarePosted Jul 10, 2026, 4:44 PM
In C#, I would choose a struct when the type is small, lightweight, and represents a single value, such as a point, date, or identifier. Structs are value types, so they are often stored inline and can reduce heap allocations and garbage collection overhead.
A class is usually the better choice for larger, mutable, or behavior-rich objects that need inheritance, polymorphism, or object identity.
Regarding performance, structs can be faster when they are small and immutable because they avoid additional heap allocations and improve cache locality. However, large structs can hurt performance because they are copied by value whenever they are assigned or passed to methods.
As a practical rule of thumb:
Use readonly struct for small immutable value types.
Use class for complex domain objects and entities.
If a struct becomes large or frequently copied, consider switching it to a class or passing it by in to avoid unnecessary copying.
In most real-world applications, the biggest performance benefit of structs comes from reducing allocations, while the biggest risk is excessive copying of large structs.