What Is Polymorphism?

Polymorphism is a theory in type theory and programming languages that provides a uniform interface to entities of different types. This is achieved by using a single symbol to represent multiple different types. However, this theory is often abused or misunderstood. Here are some common examples of polymorphism.

Subtype polymorphism

Subtype polymorphism is the ability to have multiple versions of a class with different characteristics. For example, if a class is called “Dogs” and has two subtypes named “Golden Retriever” and “Basset Hound,” then that class can have multiple instances of the same function. The function can also have functions that operate on both subtypes of the same class.

In the context of a type system, the language must allow a single entity to have multiple types. A simple example of polymorphism is subtype polymorphism, which is different from parametric polymorphism. In contrast, parameterized polymorphism is the process of passing a single object between multiple classes.

A subtype can have different values for each of its fields. For example, a language might allow floating point values where integer values are expected. The language may also define a generic type Number, a supertype of both integers and reals.

Genetic polymorphism

Polymorphism is the result of variation in the genetic makeup of a population. It is defined as the presence of more than one allele for the same gene at the same locus. These alleles must be at least one percent different from being genetically distinct. Biological organisms have evolved different genotypes for various niches, and this variation has been retained in the population.

Genetic polymorphism is a consequence of evolution and is an essential hereditary trait. It is an adaptation to the environment and is influenced by natural selection. For example, butterflies mimic poisonous species. Another example of genetic polymorphism is blood groups. Human blood contains four different blood groups based on DNA sequences. Different regions of the world have different proportions of different blood groups.

Polymorphisms can also be functional. They alter the gene’s function, but their exact effect is unknown. Researchers can infer their functions from the location of the polymorphisms. In some cases, polymorphisms are located in regions of high functional interest. Alternatively, they may occur in regions that have solid interspecies homology.

Ad hoc polymorphism

Ad hoc polymorphism refers to the fact that a function can be used with arguments of different types. It is a type of polymorphism, and a polymorphic function can have multiple distinct implementations. It can be a helpful feature in a program that allows users to create a flexible and robust program.

One way to use ad hoc polymorphism is in the way a function is called. For example, the ‘+’ symbol can be used to denote two different functions, one that adds two integers and one that adds two floats. This is an example of ad hoc polymorphism, and almost all programming languages support it.

Polymorphism is common in object-oriented programming languages, such as Java. Many of these languages also support operator overloading. However, there are disadvantages to ad hoc polymorphism. Non-dynamically typed languages, on the other hand, lack type classes and have longer function names. Some see these as advantages, while others view this as a disadvantage.

Dynamic polymorphism

Dynamic polymorphism is a programming technique in which an object inherits methods and behaviors from its parent class. The code that implements dynamic polymorphism uses dynamic binding, which determines the execution of methods at runtime. The compiler generates object code based on this binding. In addition, static methods cannot be overridden, and the method name, number, and type of parameters must match those of the parent class.

Dynamic polymorphism can be implemented in several ways. One way is using templates. In a template, a base version of the function is stored. The user can then cast this pointer to the desired object and call a function relating to the object’s type. This approach reduces the overhead of maintaining a virtual table by eliminating the need to maintain a pointer to it. In addition, templates provide explicit object resolution mechanisms and help developers avoid the common mistake of forgetting to declare a base function virtual.

The other way to create polymorphic code is by overriding methods from the superclass. This way, a developer can tailor the behavior of a class to suit the needs of his application. Although a superclass and a subclass have the same name, they have different functionality. A simple example of this is a coffee machine. Its parent class, ABC, implements a selection method called brew coffee. The subclass implements the same method but overrides the method to provide custom functionality.