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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.
In object-oriented programming, polymorphism more specifically refers to subtyping or subtype polymorphism, where a function can work with a specific interface and thus manipulate entities of different classes in a uniform manner. [61] For example, imagine a program has two shapes: a circle and a square. Both come from a common class called ...
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 .
Virtual functions allow a program to call methods that don't necessarily even exist at the moment the code is compiled. [citation needed] In C++, virtual methods are declared by prepending the virtual keyword to the function's declaration in the base class. This modifier is inherited by all implementations of that method in derived classes ...
Impredicative polymorphism (also called first-class polymorphism) is the most powerful form of parametric polymorphism. [ 1 ] : 340 In formal logic , a definition is said to be impredicative if it is self-referential; in type theory, it refers to the ability for a type to be in the domain of a quantifier it contains.
In programming language theory, subtyping (also called subtype polymorphism or inclusion polymorphism) is a form of type polymorphism.A subtype is a datatype that is related to another datatype (the supertype) by some notion of substitutability, meaning that program elements (typically subroutines or functions), written to operate on elements of the supertype, can also operate on elements of ...
For the code to function as before, a decryption function is added to the code. When the code is executed, this function reads the payload and decrypts it before executing it in turn. Encryption alone is not polymorphism. To gain polymorphic behavior, the encryptor/decryptor pair is mutated with each copy of the code.
In some systems for object-oriented programming such as the Common Lisp Object System (CLOS) [1] and Dylan, a generic function is an entity made up of all methods having the same name. Typically a generic function is an instance of a class that inherits both from function and standard-object .