Structures versus classes

Classes and structures different in several subtle and not so subtle ways.

Feature	Structures	Classes
Inheritance	Structures can inherit any type other than classes besides Object	Classes can inherit any type
By reference versus by value	Instances of structures are normally by value; to get a By Reference location, use the ref type modification operator	Instances of classes are normally stored in references; to get a By Value location, use the byvalue type modification operator
Interface implementation	Structures can't themselves implement interfaces	Classes can implement interfaces as needed
Bitfields and unions	Structures can use these as needed	Classes may not declare bitfields or unions; to do that, drive from a structure that does it for you; Classes can, however, use a typed union