Yes, the derived class includes the memory of the base class. The derived class inherits everything in the base class, data and function, and provides additional data and function as needed.
Multiple inheritance occurs when a class is derived directly from two or more base classes. class b1 {}; class b2 {}; class d: public b1, public b2 {}; // multiple inheritance class
Multi-level inheritance involves at least 3 classes, a, b and c, such that a is derived from b, and b is derived from c. c is therefore the least-derived base class, b is an intermediate base class and a is the most-derived class.
When you derive a class (the sub-class) from a base class using protected access, all public members of the base class become protected members of the derived class, while protected members of the base class will remain protected. Private members are never inherited so they remain private to the base class. By contrast, if you use public inheritance, the public members of the base class remain public to the derived class, while protected members of the base class remain protected in the derived class. If you use private inheritance, both the public and protected members of the base class become private to the derived class. Note that accessibility cannot be increased, only reduced or left the same. That is, a protected member of a base class cannot be inherited as a public member of a derived class -- it can only be declared private or remain protected. Note also that accessibility is viewed from outside of the derived class. That is, all members of a base class other than the private members are inherited by the derived class and are therefore fully accessible to the derived class. But from outside of the derived class, all base class accessibility is determined by the access specified by the type of inheritance.
There are only two types of inheritance in object oriented programming: Single inheritance: where a class inherits directly from just one base class. Multiple inheritance: where a class inherits directly from two or more base classes. Multi-level inheritance is often thought of as being a separate type of inheritance, however inheritance relates to a derived class and those that it directly inherits from. If a base class is itself a derived class (an intermediate class), then its base class or classes are simply indirect base classes of the derivative. But in isolation, the intermediate class either uses single or multiple inheritance, even if its base class or classes are also intermediates. Virtual inheritance is also thought of as being a separate type, however virtual inheritance doesn't change the relationship between classes within the hierarchy. the only difference virtual inheritance makes is that the virtual base class or classes are constructed by the most-derived class within the current hierarchy, rather than by their most direct descendants. In this way, only one instance of each virtual base exists in the hierarchy, rather than multiple instance as would normally exist. The actual inheritance is still single or multiple, however.
False. A virtual base class is one that is common to two or more derived classes that are themselves base classes, and that may be combined through multiple inheritance. By declaring the common base class to be virtual in its direct derivatives, only one instance of the common base class exists in the multiple-inheritance classes.
Multiple inheritance occurs when a class is derived directly from two or more base classes. class b1 {}; class b2 {}; class d: public b1, public b2 {}; // multiple inheritance class
Multi-level inheritance involves at least 3 classes, a, b and c, such that a is derived from b, and b is derived from c. c is therefore the least-derived base class, b is an intermediate base class and a is the most-derived class.
Public, protected and private inheritance determine how the public and protected base class members are inherited by the derived class. Private members are never inherited and are therefore unaffected by the type of inheritance (they remain private to the base class). The following table summarises how inheritance affects accessibility of base class members with respect to the derived class: public inheritanceprotected inheritanceprivate inheritancepublic member of base classpublic member of derived classprotected member of derived classprivate member of derived classprotected member of base classprotected member of derived classprotected member of derived classprivate member of derived classprivate member of base classprivate member of base classprivate member of base classprivate member of base class Note that accessibility to individual public and protected base class members can be overridden within the derived class, regardless of the type of inheritance specified.
Single, multiple, multi-level, hierarchical and hybrid/virtual inheritance. Single inheritance applies when one class inherits from just one base class. Multiple inheritance applies when one class inherits from two or more base classes. Multi-level inheritance applies to a class that inherits from at least one base class that is itself derived from another base class. Hierarchical inheritance applies to a base class that is inherited by two or more separate derived classes. Hybrid inheritance combines multiple inheritance, multi-level inheritance and hierarchical inheritance. That is, where A is a common base class of derived classes B and C, and B and C are both base classes of derived class D. Hybrid inheritance is often used with virtual inheritance where B and C inherit from A virtually rather than directly. In these cases, the virtual base class is instantiated by the most-derived class in the hierarchy, D, and this instance is then shared by both B and C.
Public derivation or public inheritance means that all the public members of the base calls are declared public in the derived class while the protected members remain protected. Protected inheritance means all the public members of the base class are declared protected in the derived class, as are the protected members. Private inheritance means all the public and protected members of the base class are declared private in the derived class. Private members of the base class are never inherited and are therefore unaffected by inheritance. Note that regardless of the type of inheritance specified, individual non-private members of the base class can be inherited with public or protected access as required of the derived class. The type of inheritance can be therefore be thought of as being the default inheritance for all base class members which can (optionally) be overridden for specific members where required.
Multiple Inheritance : we can inherit more than one class in the same class. Multi-Level Inheritance: where one class can inherit only one base class and the derived class can become base class of some other class.
struct A {}; // base class struct B : A {} // derived class (single inheritance).
Inheritance in C++ and in other Object Oriented languages is the creation of a class that incorporates a different class. The child (or derived) class "inherits" all of the elements (attributes and methods) of the parent (or base) class. Depending on the design of the base class, the derived class can use methods and attributes of the base class as if they were its own. Typically, however, attributes of the base class are private to the base class and inaccessible to the derived class so as to maintain class hierarchy and data encapsulation.
When you derive a class (the sub-class) from a base class using protected access, all public members of the base class become protected members of the derived class, while protected members of the base class will remain protected. Private members are never inherited so they remain private to the base class. By contrast, if you use public inheritance, the public members of the base class remain public to the derived class, while protected members of the base class remain protected in the derived class. If you use private inheritance, both the public and protected members of the base class become private to the derived class. Note that accessibility cannot be increased, only reduced or left the same. That is, a protected member of a base class cannot be inherited as a public member of a derived class -- it can only be declared private or remain protected. Note also that accessibility is viewed from outside of the derived class. That is, all members of a base class other than the private members are inherited by the derived class and are therefore fully accessible to the derived class. But from outside of the derived class, all base class accessibility is determined by the access specified by the type of inheritance.
Hierarchical inheritance is a type of inheritance in object-oriented programming where classes are organized in a hierarchical structure. It means that a derived class can inherit attributes and methods from a base or parent class, and it can further be inherited by other classes. This allows for code reuse and promotes modularity in the program.
By visibility I assume you mean member accessibility. C++ uses three levels of accessibility: private, protected and public. Private members are only accessible to the class itself and friends of the class. Protected members are the same as private members except derived classes also have access. Public members are fully accessible. With regards inheritance, base class members with greater access than that specified are reduced to the specified access in the derived class. Thus public inheritance has no effect on base class member access. Protected inheritance reduces public members of the base class to protected members of the derived class. Private inheritance reduces both public and protected members of the base class to private members of the derived class. Private members of the base class are never inherited, thus they always remain private to the base class. Note that access to base class members can never be increased through inheritance, only reduced or kept the same. However, as well as defining an overall inheritance access, you can also specify member-wise inheritance access. Thus you could use public inheritance overall, but specify certain public members of the base class to be protected or private in the derived class and/or certain protected members of the base class to be private members of the derived class.
There are only two types of inheritance in object oriented programming: Single inheritance: where a class inherits directly from just one base class. Multiple inheritance: where a class inherits directly from two or more base classes. Multi-level inheritance is often thought of as being a separate type of inheritance, however inheritance relates to a derived class and those that it directly inherits from. If a base class is itself a derived class (an intermediate class), then its base class or classes are simply indirect base classes of the derivative. But in isolation, the intermediate class either uses single or multiple inheritance, even if its base class or classes are also intermediates. Virtual inheritance is also thought of as being a separate type, however virtual inheritance doesn't change the relationship between classes within the hierarchy. the only difference virtual inheritance makes is that the virtual base class or classes are constructed by the most-derived class within the current hierarchy, rather than by their most direct descendants. In this way, only one instance of each virtual base exists in the hierarchy, rather than multiple instance as would normally exist. The actual inheritance is still single or multiple, however.