Why are interfaces in .Net reference types?

Question

Why are interfaces reference types? As far as I understand, an interface is a contract between classes (or structs), so why is it a type at all? I would have thought it is n

Answer 1

They're reference types because value types have a fixed size at compile-time, so that they can be allocated on the stack. Reference types are pointers, so the pointers are constant-size but they can point to memory of any size.