A.7. Structs

Structs are data structures that are defined similarly to classes. The difference is that a struct is a value type rather than a reference type like a class. When a variable is of a class type, it contains a reference to an instance of the class (or null). A struct variable directly contains the members of the struct rather than being a reference to an object elsewhere in memory. This is generally useful for performance or memory optimization: a large array of structs can be much quicker to create than the same size array of objects. In some situations using structs can be slower, though, particularly when assigning or passing them as parameters (because all their member data needs to be copied).

Struct definitions look like this: