struct vs class

[Jonathan M Davis]

On Sunday 14 November 2010 03:08:49 spir wrote:
> Hello,
> 
> 
> There seems to be 2 main differences between structs & classes:
> 1. structs instances are direct values, implement value semantics; while
> class instances are referenced (actually "pointed") 2. classes can be
> subtyped/subclassed in a simple way; structs cannot be really subtyped --
> but there is the "alias this" hack

The main thing to remember between structs and classes is that classes are 
polymorphic. If you want polymorphism, use a class. If you don't use a struct. 
Now, if you want a type which is _always_ a reference, then you should probably 
choose a class, but it's quite easy to have a struct which is a reference type 
by having its member variables are on the heap and don't get deep copied be a 
postblit constructor. It is more immediately clear, though, that a class is a 
reference type.

You can get more nuanced on the reasons why you should pick a struct or a class, 
but polymorphism is really what it generally comes down to. If you never intend 
to subclass it or have it implement interfaces, then it should probably be a 
struct.

- Jonathan M Davis