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The curiously recurring template pattern (CRTP) is an idiom, originally in C++, in which a class X derives from a class template instantiation using X itself as a template argument. [1] More generally it is known as F-bound polymorphism, and it is a form of F-bounded quantification.
The C++ examples in this section demonstrate the principle of using composition and interfaces to achieve code reuse and polymorphism. Due to the C++ language not having a dedicated keyword to declare interfaces, the following C++ example uses inheritance from a pure abstract base class.
Polymorphism can be distinguished by when the implementation is selected: statically (at compile time) or dynamically (at run time, typically via a virtual function). This is known respectively as static dispatch and dynamic dispatch, and the corresponding forms of polymorphism are accordingly called static polymorphism and dynamic polymorphism.
[citation needed] In C++ private inheritance can be used as a form of implementation inheritance without substitutability. Whereas public inheritance represents an "is-a" relationship and delegation represents a "has-a" relationship, private (and protected) inheritance can be thought of as an "is implemented in terms of" relationship. [16]
Some languages like Go do not support inheritance at all. Go states that it is object-oriented, [37] and Bjarne Stroustrup, author of C++, has stated that it is possible to do OOP without inheritance. [38] The doctrine of composition over inheritance advocates implementing has-a relationships using composition instead of inheritance. For ...
Thought dates = new Advice (); // Polymorphism dates. message (); // Prints "Warning: Dates in calendar are closer than they appear." When a subclass contains a method that overrides a method of the superclass, then that (superclass's) overridden method can be explicitly invoked from within a subclass's method by using the keyword super . [ 3 ] (
Since C++ does not support late binding, the virtual table in a C++ object cannot be modified at runtime, which limits the potential set of dispatch targets to a finite set chosen at compile time. Type overloading does not produce dynamic dispatch in C++ as the language considers the types of the message parameters part of the formal message name.
Virtual inheritance ensures that only one instance of a base class exists in the inheritance graph, avoiding some of the ambiguity problems of multiple inheritance. Multiple inheritance is a C++ feature allowing a class to be derived from more than one base class; this allows for more elaborate inheritance relationships. For example, a "Flying ...