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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.
C++ does not have the keyword super that a subclass can use in Java to invoke the superclass version of a method that it wants to override. Instead, the name of the parent or base class is used followed by the scope resolution operator. For example, the following code presents two classes, the base class Rectangle, and the derived class Box.
Roberts (p. 171) gives a related example in Java, using a Class to represent a stack frame. The example given is a solution to the Tower of Hanoi problem wherein a stack simulates polymorphic recursion with a beginning, temporary and ending nested stack substitution structure. [5]
Ad hoc polymorphism is a dispatch mechanism: control moving through one named function is dispatched to various other functions without having to specify the exact function being called. Overloading allows multiple functions taking different types to be defined with the same name; the compiler or interpreter automatically ensures that the right ...
As an example, an abstract base class MathSymbol may provide a pure virtual function doOperation(), and derived classes Plus and Minus implement doOperation() to provide concrete implementations. Implementing doOperation() would not make sense in the MathSymbol class, as MathSymbol is an abstract concept whose behaviour is defined solely for ...
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 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 example, the use of the << operator in C++ a << b shifts the bits in the variable a left by b bits if a and b are of an integer type, but if a is an output stream then the above code will attempt to write a b to the stream.