Classes versus Structs
Advantages of classes
Their objects are referenced through pointers and can therefore
be linked into dynamic data structures such as lists, trees and
Objects of classes are not stored in the stack frame of the method
that created them. If they are rooted in global variables the survive
the method that created them.
In contrast to structs, classes can take advantage of inheritance
and dynamic binding.
Advantages of structs
Their objects are not referenced through pointers. Accessing one of
their fields does not require dereferencing a pointer. Therefore this
access is more efficient than an access to a field of a class.
Methods of structs are not called using dynamic binding (except
interface methods). Therefore calling a method of a struct is usually more
efficient than calling a method of a class.
Objects of a struct type are stored in the stack frame of the method
in which they are declared. Their storage is automatically released
when this method ends. Therefore they put no burden on the
Structs should be used for light-weight data types, which are used
locally within a method and which are not linked into dynamic data
structures. Classes, on the other hand, should be used for heavy-weight
objects that should survive the method in which they were created.
Objects of class types are also used if they need to be linked
into dynamic data structures, if their classes should be extended,
or if dynamically-bound method calls are required.