Chapter 8 Quick Reference

To	Do this
Define an abstract base class.	Use the __abstract keyword in the class definition. For example: __gc __abstract class MyBase { ... };
Define a derived class.	In the derived class definition, use a colon, followed by public, followed by the name of the base class. For example: __gc class MyDerived : public MyBase { ... };
Construct derived objects.	In the derived-class constructor, use a member initialization list to call the base-class constructor. For example: MyDerived::MyDerived(int bdata, int ddata) : MyBase(bdata), derivedData(ddata) { ... }
Enable derived classes to access members in the base class while denying access to unrelated classes.	Declare the members as protected in the base class. For example: __gc __abstract class MyBase { protected: int dataVisibleToDerivedClass; ... };
Define overridable member functions in the base class.	Declare the member functions as virtual in the base class. For example: __gc __abstract class MyBase { protected: virtual void myOverridableFunction(); ... };
Specify base-class member functions that must be overridden by derived classes.	Declare the member functions as virtual in the base class. After the closing parenthesis, append = 0. For example: __gc __abstract class MyBase { protected: virtual void myMustBeOverridden() = 0; ... };
Prevent a class from being derived from.	Use the __sealed keyword in the class definition. For example: __gc __sealed class MySealedClass { ... };
Define an interface.	Use the __interface keyword. For example: __gc __interface IMyInterface { void function1(int n); int function2(double d); };
Implement an interface.	Use the same syntax as for inheritance. Implement all the required functions in your class. For example: __gc class MyImplementingClass : public IMyInterface { public: void function1(int n); int function2(double d); // Other members, as needed ... };