A Slice class definition is similar to a structure definition, but uses the class
keyword. For example:
class TimeOfDay { short hour; // 0 - 23 short minute; // 0 - 59 short second; // 0 - 59 };
Apart from the keyword class
, this definition is identical to the structure example. You can use a Slice class wherever you can use a Slice structure (but, as we will see shortly, for performance reasons, you should not use a class where a structure is sufficient). Unlike structures, classes can be empty:
class EmptyClass {}; // OK struct EmptyStruct {}; // Error
Much the same design considerations as for empty interfaces apply to empty classes: you should at least stop and rethink your approach before committing yourself to an empty class.
You can specify a default value for a class data member that has one of the following types:
- An integral type (
byte
,short
,int
,long
) - A floating point type (
float
ordouble
) string
bool
enum
For example:
class Location { string name; Point pt; bool display = true; string source = "GPS"; };
The legal syntax for literal values is the same as for Slice constants, and you may also use a constant as a default value. The language mapping guarantees that data members are initialized to their declared default values using a language-specific mechanism.