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Topics

C++ Basics

Introduction to C++C++ History and EvolutionC++ Environment SetupC++ First ProgramC++ SyntaxC++ CommentsC++ Data TypesC++ VariablesC++ ConstantsC++ KeywordsC++ OperatorsC++ Input/Output

C++ Control Structures

C++ If-Else StatementsC++ Switch StatementsC++ For LoopsC++ While LoopsC++ Do-While LoopsC++ Break and ContinueC++ Goto Statement

C++ Functions

C++ Function BasicsC++ Function ParametersC++ Function OverloadingC++ Inline FunctionsC++ RecursionC++ Default ArgumentsC++ Lambda Expressions

C++ Arrays and Strings

C++ ArraysC++ Multidimensional ArraysC++ C-style StringsC++ String ClassC++ String FunctionsC++ String Streams

C++ Pointers and References

C++ Pointers BasicsC++ Pointer ArithmeticC++ ReferencesC++ Pointers vs ReferencesC++ Dynamic Memory AllocationC++ Smart Pointers

C++ Object-Oriented Programming

C++ Classes and ObjectsC++ Constructors and DestructorsC++ Access SpecifiersC++ EncapsulationC++ InheritanceC++ PolymorphismC++ Virtual FunctionsC++ Abstract ClassesC++ Interfaces (Pure Virtual)C++ Friend Functions and Classes

C++ Templates

C++ Function TemplatesC++ Class TemplatesC++ Template SpecializationC++ Variadic Templates

C++ Exception Handling

C++ Try-Catch BlocksC++ Throwing ExceptionsC++ Custom ExceptionsC++ Exception Specifications

C++ File Handling

C++ File I/O StreamsC++ Reading from FilesC++ Writing to FilesC++ Binary File Operations

C++ Standard Template Library

C++ STL ContainersC++ STL AlgorithmsC++ STL IteratorsC++ STL Function Objects

C++ Advanced Topics

C++ NamespacesC++ Preprocessor DirectivesC++ Type CastingC++ MultithreadingC++ Regular ExpressionsC++ Move SemanticsC++ Rvalue References

C++ Memory Management

C++ Stack vs HeapC++ Memory LeaksC++ Garbage CollectionC++ Custom Allocators

C++ Best Practices

C++ Coding StandardsC++ Performance OptimizationC++ Debugging TechniquesC++ Unit Testing

C++ Polymorphism

Polymorphism is a fundamental concept in object-oriented programming that allows objects of different types to be treated as objects of a common base class. In C++, polymorphism enables you to write more flexible and extensible code.

Types of Polymorphism in C++

C++ supports two main types of polymorphism:

  1. Compile-time polymorphism: Achieved through function overloading and operator overloading.
  2. Runtime polymorphism: Implemented using virtual functions and inheritance.

This guide focuses on runtime polymorphism, which is the more powerful and flexible form.

Runtime Polymorphism

Runtime polymorphism allows a program to decide which function to call at runtime, based on the actual type of the object. This is achieved through virtual functions and inheritance.

Virtual Functions

Virtual functions are member functions declared in a base class and overridden in derived classes. They are declared using the virtual keyword.


class Shape {
public:
    virtual double area() const {
        return 0;
    }
};

class Circle : public Shape {
private:
    double radius;
public:
    Circle(double r) : radius(r) {}
    double area() const override {
        return 3.14159 * radius * radius;
    }
};

In this example, area() is a virtual function in the base class Shape and is overridden in the derived class Circle.

Using Polymorphism

To utilize polymorphism, you typically use pointers or references to the base class:


Shape* shape = new Circle(5);
double area = shape->area(); // Calls Circle::area()
delete shape;

This code demonstrates how a base class pointer can be used to call the appropriate derived class function.

Benefits of Polymorphism

  • Flexibility: Write code that can work with objects of multiple types.
  • Extensibility: Easily add new derived classes without modifying existing code.
  • Code reuse: Implement common functionality in base classes.
  • Abstraction: Work with high-level concepts without worrying about specific implementations.

Best Practices

  1. Always declare destructors as virtual in base classes to ensure proper cleanup of derived objects.
  2. Use the override keyword when overriding virtual functions to catch errors at compile-time.
  3. Consider making base classes abstract if they're not meant to be instantiated directly.
  4. Be mindful of the performance impact of virtual functions, especially in performance-critical code.

Conclusion

Polymorphism is a powerful feature in C++ that enables more flexible and maintainable code. By mastering this concept, you can create more robust and extensible object-oriented designs. Remember to use it judiciously and consider the performance implications in your specific use case.

For more advanced topics related to polymorphism, explore abstract classes and interfaces (pure virtual functions) in C++.