How Does C Achieve Polymorphism, and What Are Its Different Types?

Polymorphism in C

Introduction

Polymorphism allows different types of objects to respond to the same message, such as a function call, in a uniform way. C provides multiple mechanisms to achieve polymorphism.

Explicit Programmer-Specified Polymorphism

Overloading: Functions with the same name but different parameter types are used to provide different implementations for different types.

Templates: Classes and functions can be defined using generic type parameters, allowing a single function to work with multiple types.

Virtual Dispatch: Functions in classes can be declared virtual, which allows derived classes to override the function and provide their own implementations.

Other Related Mechanisms

Compiler-Provided Polymorphism: Certain built-in operators and operations are overloaded by the compiler to support polymorphism.

Conversions: Implicit and explicit conversions can be used to convert between different types, facilitating interaction between different data types.

Coercion/Casting: Implicit or explicit type conversions can be performed manually or through casts.

Categorization Based on Implementation

Compile-time Polymorphism: Polymorphism is handled by the compiler during compilation. This includes overloading and templates.

Run-time Polymorphism: Polymorphism is handled dynamically during program execution. This includes virtual dispatch.

Types of Polymorphism

Ad-hoc Polymorphism: Polymorphism achieved by specifying individual cases for each type that needs to be supported.

Parametric Polymorphism: Polymorphism achieved using generic types without specifying specific type operations. This is commonly seen with templates and macros.

Discussion

• Understanding the mechanisms of polymorphism empowers developers to use the technique effectively.
• Different types of polymorphism suit different scenarios, considering factors such as performance and reusability.

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